maven-plugins/pmd/rulesets/experimental.xml

<?xml version="1.0"?>

<ruleset name="experimental">
  <description>
This is the sandbox.
  </description>

 <!--<rule name="UnnecessaryCast"
        message="Avoid unnecessary casts"
        class="net.sourceforge.pmd.rules.UnnecessaryCastRule">
    <description>
A variable is cast to itself, one of its supertypes or one of its interfaces.  Usually
indicates that the programmer is not clear on the class structure they
are working with.
    </description>

    <example>
<![CDATA[
public Collection doSomething() {
  List list = new ArrayList();

  return (Collection) list; // Unnecessary Cast
}
]]>
    </example>
  </rule>

  <rule name="PositionalIterator"
        message="Avoid positional iterators"
        class="net.sourceforge.pmd.rules.design.PositionalIteratorRule">
    <description>
    Avoid positional iterators.   This doesn't work yet,
    it breaks on stuff like this:
    public class Foo {
     private int baz = true;
     public void bar(Iterator i) {
      Object x = null;
      while (i.hasNext()) {
       if (baz) {
        x = i.next();
       } else {
        x = new Runnable() {public void run() {Object bif = i.next();}}
       }
      }
     }
    }
    See javax.security.auth.Subject.java, inner class SecureSet, method removeAll(), around line 1092 for a good example.
    </description>

    <example>
<![CDATA[
public class PositionalIterators {
 public void foo(Iterator i) {
  while(i.hasNext()) {
   Object one = i.next();
   // 2 calls to next() inside the loop == bad!
   Object two = i.next();
  }
 }
}
]]>
    </example>
    </rule>

 <rule name="StringConcatenation"
        message="Consider replacing String concatenation inside loops with a StringBuffer"
        class="net.sourceforge.pmd.rules.StringConcatenationRule">
    <description>
    Consider replacing String concatenation inside loops with a StringBuffer
    </description>

    <example>
<![CDATA[
public class Bar {
 public String foo(Object[] someArray) {
  String list = "" ;
  for( int i = 0; i < someArray.length; i++ ){
   list = list + "," + someArray[i];
  }
  return list;
 }
}
]]>
    </example>
    </rule>
    -->
</ruleset>