diff --git a/src/main/org/apache/tools/ant/AntClassLoader.java b/src/main/org/apache/tools/ant/AntClassLoader.java
index 4c6fbd8f5..e38682896 100644
--- a/src/main/org/apache/tools/ant/AntClassLoader.java
+++ b/src/main/org/apache/tools/ant/AntClassLoader.java
@@ -513,7 +513,8 @@ public class AntClassLoader extends ClassLoader implements BuildListener {
      *                    Should not be <code>null</code>.
      */
     public void addSystemPackageRoot(String packageRoot) {
-        systemPackages.addElement(packageRoot + ".");
+        systemPackages.addElement(packageRoot 
+                                  + (packageRoot.endsWith(".") ? "" : "."));
     }
 
     /**
@@ -526,7 +527,8 @@ public class AntClassLoader extends ClassLoader implements BuildListener {
      *                    Should not be <code>null</code>.
      */
     public void addLoaderPackageRoot(String packageRoot) {
-        loaderPackages.addElement(packageRoot + ".");
+        loaderPackages.addElement(packageRoot
+                                  + (packageRoot.endsWith(".") ? "" : "."));
     }
 
     /**