Python PostCommit: wordcount_xlang.py hangs

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.SecurityException: Invalid signature file digest for Manifest main attributes
	at sun.security.util.SignatureFileVerifier.processImpl(SignatureFileVerifier.java:330)
	at sun.security.util.SignatureFileVerifier.process(SignatureFileVerifier.java:263)
	at java.util.jar.JarVerifier.processEntry(JarVerifier.java:275)
	at java.util.jar.JarVerifier.update(JarVerifier.java:230)
	at java.util.jar.JarFile.initializeVerifier(JarFile.java:383)
	at java.util.jar.JarFile.ensureInitialization(JarFile.java:612)
	at java.util.jar.JavaUtilJarAccessImpl.ensureInitialization(JavaUtilJarAccessImpl.java:69)
	at sun.misc.URLClassPath$JarLoader$2.getManifest(URLClassPath.java:991)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:451)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
	at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:495)