I noticed a couple improvements that could be made to Component.firePropertyChange(String, Object, Object), both based on the fact that it forwards the call on to java.beans.PropertyChangeSupport.firePropertyChange:

1) PropertyChangeSupport.firePropertyChange states that, "no event is fired if old and new values are equal and non-null." Component.firePropertyChange() behaves the same way, but this clause is missing from the JavaDoc.

2) firePropertyChange(String, Object, Object) in both PropertyChangeSupport and Component make this check:
if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
    return;
}
However, given that the Component version simply goes on to call the PropertyChangeSupport version, this check is redundant in Component.firePropertyChange().