}

    @Override
    public Boolean call() {
        try {
            return delegate.call();
        } finally {
            CompositeStoppable.stoppable(fileManager).stop();
            cleanupZipCache();
        }
    }

    /**
     * The javac file manager uses a shared ZIP cache which keeps file handles open
     * after compilation. It's supposed to be tunable with the -XDuseOptimizedZip parameter,