Index: xbean-finder/src/main/java/org/apache/xbean/finder/UrlSet.java
===================================================================
--- xbean-finder/src/main/java/org/apache/xbean/finder/UrlSet.java	(revision 811521)
+++ xbean-finder/src/main/java/org/apache/xbean/finder/UrlSet.java	(working copy)
@@ -105,7 +105,8 @@
      * @throws MalformedURLException
      */
     public UrlSet excludeJavaExtDirs() throws MalformedURLException {
-        return excludePaths(System.getProperty("java.ext.dirs", ""));
+        String extDirs = System.getProperty("java.ext.dirs");
+        return extDirs == null ? this : excludePaths(extDirs);
     }
 
     /**
@@ -115,7 +116,8 @@
      * @throws MalformedURLException
      */
     public UrlSet excludeJavaEndorsedDirs() throws MalformedURLException {
-        return excludePaths(System.getProperty("java.endorsed.dirs", ""));
+        String endorsedDirs = System.getProperty("java.endorsed.dirs");
+        return endorsedDirs == null ? this : excludePaths(endorsedDirs);
     }
 
     public UrlSet excludeJavaHome() throws MalformedURLException {