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Subject Re: Problems shutting down embedded instance
Date Wed, 01 Apr 2009 14:25:04 GMT
Hi again.
First of all, sorry about the previous messages, with the strange character codes. I hope
this message doesn't have those in it.
Second, I have found the place in OpenEJB that causes the problems for me. Please see the
comments in the code (that I have added)!

public class Memoizer<K, V> implements Computable<K, V> {
	private final ConcurrentMap<K, Future<V>> cache = new ConcurrentHashMap<K,

	private final Computable<K, V> c;

	public Memoizer(Computable<K, V> c) {
		this.c = c;

    // This method causes the NullPointerException and will
    // loop forever when that happens.
	public V compute(final K key) throws InterruptedException {
		while (true) {
			Future<V> future = cache.get(key);
			// When arriving here, future will not be null.
			if (future == null) {

				Callable<V> eval = new Callable<V>() {
					public V call() throws Exception {
						return c.compute(key);
				FutureTask<V> futureTask = new FutureTask<V>(eval);
				future = cache.putIfAbsent(key, futureTask);
				if (future == null) {
					future = futureTask;;
			try {
			     // The NullPointerException occurs when calling
			     // future.get()
				return future.get();
			} catch (ExecutionException e) {
			     // So, finally, we arrive here and print the stacktrace
			     // and go back for another NullPointerException...

If the above class were to let the exception propagate out, then it would eventually reach
the WebappClassLoader.clearReferences() in Tomcat and the clearing of static and final fields
in that particular class would be skipped and the only "problem" I would have would be a stacktrace
in the Tomcat log.
So how about it, OpenEJB people, is this fixable?
Best regards,
 Ivan A Krizsan

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