diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/QualifiableNode.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/QualifiableNode.java
index fb37ba573c..cc42a753d9 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/QualifiableNode.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/QualifiableNode.java
@@ -7,6 +7,8 @@ package net.sourceforge.pmd.lang.java.ast;
 import java.util.Arrays;
 
 /**
+ * Nodes that can be described with a qualified name.
+ *
  * @author Clément Fournier
  */
 public interface QualifiableNode {
@@ -19,8 +21,17 @@ public interface QualifiableNode {
     char PARAMLIST_SEP = ',';
     char PACKAGE_SEP = '.';
 
+    /**
+     * Returns a qualified name for this node.
+     *
+     * @return A qualified name.
+     */
     QualifiedName getQualifiedName();
 
+    /**
+     * Represents Qualified Names for use within PackageStats
+     * TODO make unit tests once the visitor is working to ensure new implementations won't break it
+     */
     class QualifiedName {
         private String[] packages = null; // unnamed package
         private String[] classes = new String[1];
@@ -29,15 +40,17 @@ public interface QualifiableNode {
         public QualifiedName() {
         }
 
+        /** Builds a QName for an operation using the QName of the enclosing class */
         public static QualifiedName makeOperationOf(QualifiedName parentClass, String operationName, String[] paramTypes) {
             QualifiedName qname = new QualifiedName();
             qname.packages = parentClass.packages;
             qname.classes = parentClass.classes;
 
-            qname.setOperation(operationName, paramTypes);
+            qname.operation = getOperationName(operationName, paramTypes);
             return qname;
         }
 
+        /** Builds a nested class QName using the QName of its immediate parent */
         public static QualifiedName makeClassOf(QualifiedName parent, String className) {
             QualifiedName qname = new QualifiedName();
             qname.packages = parent.packages;
@@ -51,18 +64,54 @@ public interface QualifiableNode {
             return qname;
         }
 
+        // Might be useful with type resolution
+        public static QualifiedName parseCanonicalName(String canon) {
+            throw new UnsupportedOperationException();
+        }
+
+        /** Returns a normalized method name (not Java-canonical!) */
+        public static String getOperationName(String methodName, String[] paramTypes) {
+            StringBuilder sb = new StringBuilder();
+            sb.append(methodName);
+            sb.append(LEFT_PARAM_SEP);
+            int last = paramTypes.length - 1;
+            for (int i = 0; i < last; i++) {
+                sb.append(paramTypes[i]);
+                sb.append(PARAMLIST_SEP);
+            }
+
+            if (last > -1) {
+                sb.append(paramTypes[last]);
+            }
+
+            sb.append(RIGHT_PARAM_SEP);
+
+            return sb.toString();
+        }
+
+        /** Is this QName describing a class? */
+        // Probably useless
         public boolean isClass() {
             return classes[0] != null && operation == null;
         }
 
+        /** Sets the class to the specified name, truncates the array to length of one */
         public void setClass(String className) {
-            classes[0] = className;
+            if (classes.length == 1) {
+                classes[0] = className;
+                return;
+            }
+
+            classes = new String[]{className};
+
         }
 
+        // Probably useless
         public boolean isNestedClass() {
             return classes.length > 1 && operation == null;
         }
 
+        // Probably useless
         public boolean isOperation() {
             return operation != null;
         }
@@ -79,6 +128,7 @@ public interface QualifiableNode {
             return classes;
         }
 
+        // Probably useless
         public void setClasses(String[] classes) {
             this.classes = classes;
         }
@@ -87,26 +137,6 @@ public interface QualifiableNode {
             return operation;
         }
 
-
-        public void setOperation(String methodName, String[] paramTypes) {
-            StringBuilder sb = new StringBuilder();
-            sb.append(methodName);
-            sb.append(LEFT_PARAM_SEP);
-            int last = paramTypes.length - 1;
-            for (int i = 0; i < last; i++) {
-                sb.append(paramTypes[i]);
-                sb.append(PARAMLIST_SEP);
-            }
-
-            if (last > -1) {
-                sb.append(paramTypes[last]);
-            }
-
-            sb.append(RIGHT_PARAM_SEP);
-
-            this.operation = sb.toString();
-        }
-
         @Override
         public String toString() {
             StringBuilder sb = new StringBuilder();
@@ -120,7 +150,7 @@ public interface QualifiableNode {
 
                 sb.append(packages[last]);
             }
-            sb.append(LEFT_CLASS_SEP); // class delimiter is there anyway
+            sb.append(LEFT_CLASS_SEP); // class delimiter is there even if package null
 
             int last = classes.length - 1;
             for (int i = 0; i < last; i++) {