diff --git a/pmd/src/net/sourceforge/pmd/util/viewer/model/ASTModel.java b/pmd/src/net/sourceforge/pmd/util/viewer/model/ASTModel.java
index 55a8a1208c..cefdd89a54 100644
--- a/pmd/src/net/sourceforge/pmd/util/viewer/model/ASTModel.java
+++ b/pmd/src/net/sourceforge/pmd/util/viewer/model/ASTModel.java
@@ -1,13 +1,15 @@
 package net.sourceforge.pmd.util.viewer.model;
 
 
-import net.sourceforge.pmd.ast.SimpleNode;
+import java.util.ArrayList;
+import java.util.List;
 
 import javax.swing.event.TreeModelEvent;
 import javax.swing.event.TreeModelListener;
 import javax.swing.tree.TreeModel;
 import javax.swing.tree.TreePath;
-import java.util.Vector;
+
+import net.sourceforge.pmd.ast.SimpleNode;
 
 
 /**
@@ -17,10 +19,10 @@ import java.util.Vector;
  * @version $Id$
  */
 
-public class ASTModel
-        implements TreeModel {
+public class ASTModel implements TreeModel {
+	
     private SimpleNode root;
-    private Vector listeners = new Vector(1);
+    private List listeners = new ArrayList(1);
 
     /**
      * creates the tree model
@@ -96,7 +98,7 @@ public class ASTModel
 
     protected void fireTreeModelEvent(TreeModelEvent e) {
         for (int i = 0; i < listeners.size(); i++) {
-            ((TreeModelListener) listeners.elementAt(i)).treeNodesChanged(e);
+            ((TreeModelListener) listeners.get(i)).treeNodesChanged(e);
         }
     }
 
diff --git a/pmd/src/net/sourceforge/pmd/util/viewer/model/AttributeToolkit.java b/pmd/src/net/sourceforge/pmd/util/viewer/model/AttributeToolkit.java
index f4cfd725f1..d6315aa414 100644
--- a/pmd/src/net/sourceforge/pmd/util/viewer/model/AttributeToolkit.java
+++ b/pmd/src/net/sourceforge/pmd/util/viewer/model/AttributeToolkit.java
@@ -20,7 +20,7 @@ public class AttributeToolkit {
      * @return formmated value
      */
     public static String formatValueForXPath(Attribute attribute) {
-        return "'" + attribute.getValue() + "'";
+        return '\'' + attribute.getValue() + '\'';
     }
 
     /**
@@ -30,7 +30,7 @@ public class AttributeToolkit {
      * @return predicate
      */
     public static String constructPredicate(Attribute attribute) {
-        return "[@" + attribute.getName() + "=" +
-                formatValueForXPath(attribute) + "]";
+        return "[@" + attribute.getName() + '=' +
+                formatValueForXPath(attribute) + ']';
     }
 }
\ No newline at end of file
diff --git a/pmd/src/net/sourceforge/pmd/util/viewer/model/SimpleNodeTreeNodeAdapter.java b/pmd/src/net/sourceforge/pmd/util/viewer/model/SimpleNodeTreeNodeAdapter.java
index e99a9c16ec..dd234db530 100644
--- a/pmd/src/net/sourceforge/pmd/util/viewer/model/SimpleNodeTreeNodeAdapter.java
+++ b/pmd/src/net/sourceforge/pmd/util/viewer/model/SimpleNodeTreeNodeAdapter.java
@@ -17,8 +17,8 @@ import java.util.List;
  * @version $Id$
  */
 
-public class SimpleNodeTreeNodeAdapter
-        implements TreeNode {
+public class SimpleNodeTreeNodeAdapter implements TreeNode {
+	
     private SimpleNode node;
     private List children;
     private SimpleNodeTreeNodeAdapter parent;
@@ -91,7 +91,7 @@ public class SimpleNodeTreeNodeAdapter
 
     public boolean isLeaf() {
         checkChildren();
-        return children.size() == 0;
+        return children.isEmpty();
     }
 
 
diff --git a/pmd/src/net/sourceforge/pmd/util/viewer/model/ViewerModel.java b/pmd/src/net/sourceforge/pmd/util/viewer/model/ViewerModel.java
index 2f2767f5bc..00b78755e1 100644
--- a/pmd/src/net/sourceforge/pmd/util/viewer/model/ViewerModel.java
+++ b/pmd/src/net/sourceforge/pmd/util/viewer/model/ViewerModel.java
@@ -1,25 +1,27 @@
 package net.sourceforge.pmd.util.viewer.model;
 
+import java.io.StringReader;
+import java.util.ArrayList;
+import java.util.List;
+
 import net.sourceforge.pmd.TargetJDKVersion;
 import net.sourceforge.pmd.ast.ASTCompilationUnit;
 import net.sourceforge.pmd.ast.ParseException;
 import net.sourceforge.pmd.ast.SimpleNode;
 import net.sourceforge.pmd.jaxen.DocumentNavigator;
+
 import org.jaxen.BaseXPath;
 import org.jaxen.JaxenException;
 import org.jaxen.XPath;
 
-import java.io.StringReader;
-import java.util.List;
-import java.util.Vector;
-
 public class ViewerModel {
-    private Vector listeners;
-    private SimpleNode rootNode;
-    private List evaluationResults;
+	
+    private List		listeners;
+    private SimpleNode	rootNode;
+    private List		evaluationResults;
 
     public ViewerModel() {
-        listeners = new Vector(5);
+        listeners = new ArrayList(5);
     }
 
     public SimpleNode getRootNode() {
@@ -99,7 +101,7 @@ public class ViewerModel {
 
     protected void fireViewerModelEvent(ViewerModelEvent e) {
         for (int i = 0; i < listeners.size(); i++) {
-            ((ViewerModelListener) listeners.elementAt(i)).viewerModelChanged(e);
+            ((ViewerModelListener) listeners.get(i)).viewerModelChanged(e);
         }
     }
 }