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    <div class="sidebarTitleDate">Release date: 30-April-2022</div>
    
    
    
        
    
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            <a href="./" role="button"
                ><i class="fa fa-home fa-lg"></i
            ></a>
            » Documentation Index   
            <a
                target="_blank"
                href="https://github.com/pmd/pmd/blob/master/docs/index.md"
                class="pull-right"
                role="button"
                ><i class="fa fa-github fa-lg"></i> Edit on GitHub</a
            >
             
        </div>
    </div>

    <hr />
</header>


<div class="post-header">
   <h1 class="post-title-main">Documentation Index</h1>
</div>



<div class="post-content" data-github-edit-url="https://github.com/pmd/pmd/blob/master/docs/index.md">

   
    <div class="summary">Welcome to the documentation site for PMD and CPD! <br/><br/>
</div>
   
    <div id="inline-toc"><!-- empty, move TOC here when screen size too small --></div>
    
  
<script src="js/jquery.shuffle.min.js"></script>

<script src="js/jquery.ba-throttle-debounce.min.js"></script>

<script src="../../js/jquery-ui.min.js"></script>

<script type="text/javascript">
// Adds a pretty animation to links to shuffle panels
$(function () {
    $('a[href^=#shuffle-panel]').click(function () {
        if (location.pathname.replace(/^\//, '') === this.pathname.replace(/^\//, '')
            && location.hostname === this.hostname) {
            var target = $(this.hash);

            target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
            if (target.length) {
                $('#topbar-content-offset').animate({
                    scrollTop: $('#grid-rule').position().top
                }, {
                    duration: 500,
                    complete: function () {
                        target.effect("highlight", {}, 1000);
                    }
                });

                return false;
            }
        }
    });
});
</script>

<h2 id="-overview">💡 Overview</h2>

<!--  You can link to an individual panel, the id is determined from the title of the panel -->
<!--  See custom/shuffle_panel.html for the details -->

<p><strong>PMD</strong> is a static source code analyzer. It finds common programming flaws like
unused variables, empty catch blocks, unnecessary object creation, and
so forth. It’s mainly concerned with <strong>Java and Apex</strong>, but <strong>supports six other
languages</strong>.</p>

<p>PMD features many <strong>built-in checks</strong> (in PMD lingo, <em>rules</em>), which are documented
for each language in our <a href="#shuffle-panel-rule-references">Rule references</a>. We
also support an extensive API to <a href="#shuffle-panel-writing-rules"><strong>write your own rules</strong></a>,
which you can do either in Java or as a self-contained XPath query.</p>

<p>PMD is most useful when <strong>integrated into your build process</strong>. It can then be
used as a quality gate, to enforce a coding standard for your codebase. Among other
things, PMD can be run:</p>
<ul>
  <li>As a <a href="pmd_userdocs_tools_maven.html">Maven goal</a></li>
  <li>As an <a href="pmd_userdocs_tools_ant.html">Ant task</a></li>
  <li>As a <a href="https://docs.gradle.org/current/userguide/pmd_plugin.html">Gradle task</a></li>
  <li>From <a href="pmd_userdocs_installation.html#running-pmd-via-command-line">command-line</a></li>
</ul>

<p><strong>CPD</strong>, the <strong>copy-paste detector</strong>, is also distributed with PMD. You can also use it
in a variety of ways, which are <a href="pmd_userdocs_cpd.html">documented here</a>.</p>

<h2 id="-download">💾 Download</h2>

<p>The latest release of PMD can be downloaded from our <a href="https://github.com/pmd/pmd/releases/latest">Github releases page</a>.</p>

<h2 id="-documentation">📖 Documentation</h2>

<p>The rest of this page exposes the contents of the documentation site thematically,
which you can further scope down using the blue filter buttons. To navigate the site,
you may also use the search bar in the top right, or the sidebar on the left.</p>

<h2 id="-contributors">✨ Contributors</h2>

<p>This project follows the <a href="https://github.com/all-contributors/all-contributors">all-contributors</a> specification.
Contributions of any kind welcome!</p>

<p>See <a href="pmd_projectdocs_credits.html">credits</a> for the complete list.</p>

<p><br /></p>

<div class="filter-options" id="grid-rule">
      <button class="btn btn-primary" data-group="all">All</button>
      <button class="btn btn-primary" data-group="getting_started">Getting Started</button>
      <button class="btn btn-primary" data-group="userdocs">User documentation</button>
      <button class="btn btn-primary" data-group="extending">Extending PMD</button>
      <button class="btn btn-primary" data-group="contributing">Contributing</button>
</div>

<div class="container-fluid">
<div id="grid" class="row">

<!--  TODO the "getting started" panel is not that useful. It would be better to make a page series. -->
    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;getting_started&quot;]" id="shuffle-panel-getting-started">
    <div class="panel panel-default">


        

        <div class="panel-heading text-center">Getting started</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                These pages summarize the gist of PMD usage to get you started quickly.
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_installation.html">Installation and basic CLI usage</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_making_rulesets.html">Making rulesets</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_configuring_rules.html">Configuring rules</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_writing_rules_intro.html">Introduction to writing PMD rules</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
            </ul>
        </div>
    </div>
</div>



    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;userdocs&quot;]" id="shuffle-panel-rule-references">
    <div class="panel panel-default">


        
            <div class="panel-heading text-center">
                     <span class="fa-stack fa-5x">
                       <i class="fa fa-circle fa-stack-2x text-secondary"></i>
                       <i class="fa fa-database fa-stack-1x fa-inverse"></i>
                     </span>
            </div>
        

        <div class="panel-heading text-center">Rule references</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                Pick your language to find out about the rule it supports.
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_apex.html">Apex</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_ecmascript.html">Ecmascript</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_java.html">Java</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_jsp.html">Java Server Pages</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_pom.html">Maven POM</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_modelica.html">Modelica</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_plsql.html">PLSQL</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_vf.html">Salesforce VisualForce</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_vm.html">VM</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_xml.html">XML</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_xsl.html">XSL</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_rules_scala.html">Scala</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
            </ul>
        </div>
    </div>
</div>


    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;userdocs&quot;, &quot;extending&quot;, &quot;contributing&quot;]" id="shuffle-panel-writing-rules">
    <div class="panel panel-default">


        

        <div class="panel-heading text-center">Writing rules</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                These pages document the process of writing and testing custom rules and metrics for PMD.
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_writing_rules_intro.html">Introduction to writing PMD rules</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_your_first_rule.html">Your first rule XPath</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_writing_xpath_rules.html">Writing XPath rules</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_writing_java_rules.html">Writing a custom rule</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_designer_reference.html">The rule designer</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_defining_properties.html">Defining rule properties</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_metrics_howto.html">Using and defining code metrics for custom rules</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_rule_guidelines.html">Rule guidelines</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_testing.html">Testing your rules</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_extending_writing_pmd_rules.html">Writing a custom rule</a></li>
                    
                
            </ul>
        </div>
    </div>
</div>


    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;userdocs&quot;]" id="shuffle-panel-usage-and-configuration">
    <div class="panel panel-default">


        
            <div class="panel-heading text-center">
                     <span class="fa-stack fa-5x">
                       <i class="fa fa-circle fa-stack-2x text-secondary"></i>
                       <i class="fa fa-cog fa-stack-1x fa-inverse"></i>
                     </span>
            </div>
        

        <div class="panel-heading text-center">Usage and configuration</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                Learn how to build effective and versatile rulesets.
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_installation.html">Installation and basic CLI usage</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_making_rulesets.html">Making rulesets</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_configuring_rules.html">Configuring rules</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_best_practices.html">Best Practices</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_suppressing_warnings.html">Suppressing warnings</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_incremental_analysis.html">Incremental Analysis</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_cli_reference.html">PMD CLI reference</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_report_formats.html">Report formats for PMD</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_cpd.html">Finding duplicated code with CPD</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_cpd_report_formats.html">Report formats for CPD</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
            </ul>
        </div>
    </div>
</div>



    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;contributing&quot;]" id="shuffle-panel-contributing">
    <div class="panel panel-default">


        
            <div class="panel-heading text-center">
                     <span class="fa-stack fa-5x">
                       <i class="fa fa-circle fa-stack-2x text-secondary"></i>
                       <i class="fa fa-github fa-stack-1x fa-inverse"></i>
                     </span>
            </div>
        

        <div class="panel-heading text-center">Contributing</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                If you'd like to help us build PMD, these topics may interest you. See you around!
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_development.html">Developer Resources</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_building.html">Building PMD from source</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_writing_documentation.html">Writing documentation</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_roadmap.html">Roadmap</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_how_pmd_works.html">How PMD Works</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_pmdtester.html">Pmdtester</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_rule_deprecation_policy.html">Rule deprecation policy</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_experimental_ast_dump.html">Creating XML dump of the AST</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
            </ul>
        </div>
    </div>
</div>




    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;userdocs&quot;]" id="shuffle-panel-tools-and-integrations">
    <div class="panel panel-default">


        

        <div class="panel-heading text-center">Tools and integrations</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                These pages describe solutions that integrate PMD within your build process.
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_tools_maven.html">Maven PMD Plugin</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_tools_gradle.html">Gradle</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_tools_ant.html">Ant Task Usage</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_tools_java_api.html">PMD Java API</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_tools_ci.html">Continuous Integrations plugins</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_userdocs_tools.html">Tools / Integrations</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
            </ul>
        </div>
    </div>
</div>


    <!-- Argument summary: -->

<!-- tags: comma-separated tags determining the pages included in the panel -->
<!-- except_tags: comma-separated tags to filter out some pages -->

<!-- A page is included if it has all the include tags and none of the exclude tags -->


<!-- title: Display title of the panel -->
<!-- description: Description of the panel -->
<!-- datagroups: json array containing the data groups for the shuffle logic -->

<!-- image (optional) : Name of the image to use, as a css class, eg "fa-list" -->
<!-- titlemaker (optional) : name of a variable that's evaluated to determine the displayed title of the page. Default is page.title -->









<div class="col-xs-6 col-sm-4 col-md-4" data-groups="[&quot;contributing&quot;,&quot;extending&quot;]" id="shuffle-panel-major-contributions">
    <div class="panel panel-default">


        

        <div class="panel-heading text-center">Major contributions</div>
        <div class="panel-body">

            <p class="landing-page cat-description">
                
            </p>
            <ul>
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_major_rule_guidelines.html">Guidelines for standard rules</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_major_adding_new_language.html">Adding PMD support for a new language</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_major_adding_new_cpd_language.html">How to add a new CPD language</a></li>
                    
                
                    
                    

                    
                        <li><a href="pmd_devdocs_major_adding_new_metrics_framework.html">Adding support for metrics to a language</a></li>
                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
                    
                    

                    
                
            </ul>
        </div>
    </div>
</div>



<!-- sizer -->
<div class="col-xs-6 col-sm-4 col-md-1 shuffle_sizer"></div>

</div>
</div>

<!-- <figure><img class="docimage" src="images/pmd-logo-big.png" alt="PMD Logo"  /></figure>
 -->

<script type="text/javascript">
$(document).ready(function() {
    $('#toc').toc({ minimumHeaders: 0, listType: 'ul', showSpeed: 0, headers: 'h2,h3,h4' });
});

</script>

<!-- shuffle -->
<script>
var shuffleme = (function( $ ) {
  'use strict';

  var $grid = $('#grid'),
      $filterOptions = $('.filter-options'),
      $sizer = $grid.find('.shuffle_sizer'),

  init = function() {

    // None of these need to be executed synchronously
    setTimeout(function() {
      listen();
      setupFilters();
    }, 100);

    // instantiate the plugin
    $grid.shuffle({
      itemSelector: '[class*="col-"]',
      sizer: $sizer    
    });
  },

  // Set up button clicks
  setupFilters = function() {
    var $btns = $filterOptions.children().add('.topical-filter');
    $btns.on('click', function() {
      var $this = $(this),
          isActive = $this.hasClass( 'active' ),
          isMainTopicButton = $this.hasClass('topical-filter'),
          group = isActive ? 'all' : $this.data('group');

      // Hide current label, show current label in title
      if ( !isActive ) {
        $('.filter-options .active').add('.topical-filter.active').removeClass('active');
      }

      $this.toggleClass('active');

      // Filter elements
      $grid.shuffle( 'shuffle', group );

      // scroll to the grid
      if ( isMainTopicButton && !isActive ) {
          $('html, body').animate({
              scrollTop: $("#grid-rule").offset().top
          }, 500);
      }

    });

    $btns = null;
  },

  // Re layout shuffle when images load. This is only needed
  // below 768 pixels because the .picture-item height is auto and therefore
  // the height of the picture-item is dependent on the image
  // I recommend using imagesloaded to determine when an image is loaded
  // but that doesn't support IE7
  listen = function() {
    var debouncedLayout = $.throttle( 300, function() {
      $grid.shuffle('update');
    });

    // Get all images inside shuffle
    $grid.find('img').each(function() {
      var proxyImage;

      // Image already loaded
      if ( this.complete && this.naturalWidth !== undefined ) {
        return;
      }

      // If none of the checks above matched, simulate loading on detached element.
      proxyImage = new Image();
      $( proxyImage ).on('load', function() {
        $(this).off('load');
        debouncedLayout();
      });

      proxyImage.src = this.src;
    });

    // Because this method doesn't seem to be perfect.
    setTimeout(function() {
      debouncedLayout();
    }, 500);
  };      

  return {
    init: init
  };
}( jQuery ));



$(document).ready(function() {
  shuffleme.init();
});

    </script>

<!-- new attempt-->

<script>
    $(document).ready(function() {
     
    /* initialize shuffle plugin */
    var $grid = $('#grid');
         
    $grid.shuffle({
        itemSelector: '.item' // the selector for the items in the grid
    });
 
});</script>

<script>
$('#filter a').click(function (e) {
    e.preventDefault();
         
    // set active class
    $('#filter a').removeClass('active');
    $(this).addClass('active');
         
    // get group name from clicked item
    var groupName = $(this).attr('data-group');
         
    // reshuffle grid
    $grid.shuffle('shuffle', groupName );
});</script>



    <div class="tags">
        
    </div>



</div>


<footer>
    
    <hr />
    <div>
        This documentation is written in markdown. <br />
        If there is something missing or can be improved, edit this page on
        github and create a PR:
        <a
            target="_blank"
            href="https://github.com/pmd/pmd/blob/master/docs/index.md"
            role="button"
            ><i class="fa fa-github fa-lg"></i> Edit on GitHub</a
        >
    </div>
    
    <hr />
    <div class="row">
        <div class="col-lg-12 footer">
            &copy;2022 PMD Open Source Project. All rights
            reserved. <br />
            <span>Page last updated:</span>
            August 2017<br /> Site last generated: Apr 15, 2022 <br />
            <p>
                <img src="images/pmd-logo-small.png" alt="Company
                logo"/>
            </p>
        </div>
    </div>
</footer>


            </div>

            <!-- /.row -->
        </div>
        <!-- /.container -->
    </div>

    
    <!-- /.toc-container-wrapper -->
</div>
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