Registration has side-effect

hi,

when looking into PICO-115 I found this:

public void registerComponent(ComponentAdapter componentAdapter) throws DuplicateComponentKeyRegistrationException {
componentAdapter.setContainer(this);
componentAdapters.add(componentAdapter);
Object componentKey = componentAdapter.getComponentKey();
if (componentKeyToAdapterCache.containsKey(componentKey))

{ throw new DuplicateComponentKeyRegistrationException(componentKey); }

componentKeyToAdapterCache.put(componentKey, componentAdapter);
}

If there is a duplicate key the component will not be available by key but it will be available via getComponentInstanceOfType. Don't have a test-case but please take a look. If this is intended please document it anywhere. Its not marked as critical since most containers won't start when there is a registration error, but still its a bug IMO.