Initialization of ClassPath ends with NullPointerException

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An attempt to call com.google.common.reflect.ClassPath#from ends with NullPointerException on IBM WebSphere 8.5.5.5. The following snippet from com.google.common.reflect.ClassPath#getClassPathEntries causes issues:

URLClassLoader urlClassLoader = (URLClassLoader) classloader;
for (URL entry : urlClassLoader.getURLs()) {

getURLs() on com.ibm.ws.bootstrap.ExtClassLoader returns null:

    public URL[] getURLs() {
        return null;
    }

    public URL[] _getURLs() {
        return super.getURLs();
    }

It looks like IBM made this on purpose, so I guess reporting to Guava is more appropriate here.

[lowasser]

Is that a spec-compliant implementation? https://docs.oracle.com/javase/7/docs/api/java/net/URLClassLoader.html#getURLs() doesn't seem to suggest the possibility of returning null there.

[kluever]

As Louis points out, URLClassLoader.getURLs() doesn't say anything about returning null. Since _getURLs() isn't part of the public URLClassLoader API, we couldn't call it anyways.

Please open a bug against IBM WebSphere.