oops, NPE in previous commit...

git-svn-id: https://pmd.svn.sourceforge.net/svnroot/pmd/trunk@6748 51baf565-9d33-0410-a72c-fc3788e3496d

pmd/regress/test/net/sourceforge/pmd/lang/java/rule/design/xml/UseSingleton.xml

@@ -163,6 +163,20 @@ public enum EnumTest {
 	public static void main(String[] args) {
 		System.out.println(EnumTest.A);
 	}
+}
+     ]]></code>
+    </test-code>
+    <test-code>
+        <description><![CDATA[
+NPE in incorrect implementation...
+     ]]></description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class Foo {
+    public Foo() { }
+    public void doSomething() { }
+    public static void main(String args[]) { }
+    ;
 }
      ]]></code>
     </test-code>

pmd/src/net/sourceforge/pmd/lang/java/rule/design/UseSingletonRule.java

@@ -26,7 +26,11 @@ public class UseSingletonRule extends AbstractJavaRule {
             int methodCount = 0;
             boolean isOK = false;
             while (i > 0) {
-                Node n = decl.jjtGetChild(--i).jjtGetChild(0);
+                Node n = decl.jjtGetChild(--i);
+                if (n.jjtGetNumChildren() != 1) {
+                    break;
+                }
+                n = n.jjtGetChild(0);
                 if (n instanceof ASTFieldDeclaration) {
                     if (!((ASTFieldDeclaration) n).isStatic()) {
                         isOK = true;