@Override
    public List<File> getJarClassPath(File file) throws IOException {
        // don't bother to lock the cache, because it is thread-safe, and
        // because the worst that can happen would be to create two identical
        // jar class paths together and have one overwrite the other.
        Entry e = getEntry(file);
        if (e.jarClassPath == null)
            e.jarClassPath = super.getJarClassPath(file);
        return e.jarClassPath;
    }