Merge branch 'bug-1456'

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/unusedcode/UnusedFormalParameterRule.java

@@ -12,6 +12,7 @@ import net.sourceforge.pmd.lang.ast.Node;
 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTConstructorDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTFormalParameter;
+import net.sourceforge.pmd.lang.java.ast.ASTMarkerAnnotation;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclarator;
 import net.sourceforge.pmd.lang.java.ast.ASTName;
@@ -42,7 +43,7 @@ public class UnusedFormalParameterRule extends AbstractJavaRule {
         if (!node.isPrivate() && !getProperty(CHECKALL_DESCRIPTOR)) {
             return data;
         }
-        if (!node.isNative() && !node.isAbstract() && !isSerializationMethod(node)) {
+        if (!node.isNative() && !node.isAbstract() && !isSerializationMethod(node) && !hasOverrideAnnotation(node)) {
             check(node, data);
         }
         return data;
@@ -110,4 +111,19 @@ public class UnusedFormalParameterRule extends AbstractJavaRule {
         }
         return false;
     }
+
+    private boolean hasOverrideAnnotation(ASTMethodDeclaration node) {
+        int childIndex = node.jjtGetChildIndex();
+        for (int i = 0; i < childIndex; i++) {
+            Node previousSibling = node.jjtGetParent().jjtGetChild(i);
+            List<ASTMarkerAnnotation> annotations = previousSibling.findDescendantsOfType(ASTMarkerAnnotation.class);
+            for (ASTMarkerAnnotation annotation : annotations) {
+                ASTName name = annotation.getFirstChildOfType( ASTName.class );
+                if (name != null && (name.hasImageEqualTo( "Override" ) || name.hasImageEqualTo( "java.lang.Override" ))) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
 }

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/unusedcode/xml/UnusedFormalParameter.xml

@@ -277,6 +277,31 @@ public class Foo {
     public void readObject(ObjectInputStream stream) throws InvalidObjectException{
        throw new InvalidObjectException("Proxy required");
     }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>#1456 UnusedFormalParameter should ignore overriding methods</description>
+        <expected-problems>0</expected-problems>
+        <rule-property name="checkAll">true</rule-property>
+        <code><![CDATA[
+abstract class Base{
+  abstract public int badMethod(int arg1, String arg2);
+}
+
+class Imp1 extends Base {
+  @Override
+  public int badMethod(int arg1, String arg2) {
+    return arg2.length();
+  }
+}
+
+class Imp2 extends Base {
+  @Override
+  public int badMethod(int arg1, String arg2) {
+    return arg2.length() + arg1;
+  }
 }
         ]]></code>
     </test-code>

src/site/markdown/overview/changelog.md

@@ -72,6 +72,8 @@
     *   [#1443](https://sourceforge.net/p/pmd/bugs/1443/): RedundantFieldInitializer: False positive for small floats
 *   java-unnecessary/UselessQualifiedThis
     *   [#1422](https://sourceforge.net/p/pmd/bugs/1422/): UselessQualifiedThis: False positive with Java 8 Function
+*   java-unusedcode/UnusedFormalParameter:
+    *   [#1456](https://sourceforge.net/p/pmd/bugs/1456/): UnusedFormalParameter should ignore overriding methods
 *   java-unusedcode/UnusedPrivateField
     *   [#1428](https://sourceforge.net/p/pmd/bugs/1428/): False positive in UnusedPrivateField when local variable
         hides member variable