Index: src/main/java/java/net/URLClassLoader.java =================================================================== --- src/main/java/java/net/URLClassLoader.java (revision 487618) +++ src/main/java/java/net/URLClassLoader.java (working copy) @@ -694,7 +694,9 @@ boolean findInExtensions = searchList == urls; int i = 0; while (i < searchList.length) { - if (searchList[i] != null) { + if (searchList[i] == null) { + throw new NullPointerException("One of urls is null"); + } else { JarFile jf = null; try { URL currentUrl = searchList[i];