Merge branch 'pr-2695' into master

[java] Improve example for AvoidSynchronizedAtMethodLevel #2695

pmd-java/src/main/resources/category/java/multithreading.xml

@@ -24,7 +24,7 @@ gets it.
         <properties>
             <property name="version" value="2.0"/>
             <property name="xpath">
-                <value>//MethodDeclaration[@Synchronized= true()]</value>
+                <value>//MethodDeclaration[@Synchronized = true()]</value>
             </property>
         </properties>
         <example>
@@ -32,12 +32,27 @@ gets it.
 public class Foo {
     // Try to avoid this:
     synchronized void foo() {
+        // code, that doesn't need synchronization
+        // ...
+        // code, that requires synchronization
+        if (!sharedData.has("bar")) {
+            sharedData.add("bar");
+        }
+        // more code, that doesn't need synchronization
+        // ...
     }
     // Prefer this:
     void bar() {
+        // code, that doesn't need synchronization
+        // ...
         synchronized(this) {
+            if (!sharedData.has("bar")) {
+                sharedData.add("bar");
             }
         }
+        // more code, that doesn't need synchronization
+        // ...
+    }
 
     // Try to avoid this for static methods:
     static synchronized void fooStatic() {
@@ -45,8 +60,13 @@ public class Foo {
 
     // Prefer this:
     static void barStatic() {
+        // code, that doesn't need synchronization
+        // ...
         synchronized(Foo.class) {
+            // code, that requires synchronization
         }
+        // more code, that doesn't need synchronization
+        // ...
     }
 }
 ]]>