Did you implement equals() and hashCode()? Implementing them isn't hard. Implementing them well can be tricky, but for these purposes a simple implementation will do. Basically, with equals() you want to compare the stuff contained in the objects. With hashCode() you want to produce an integer that can be used in HashMaps. The only restriction is that, if o1.equals(o2) == true, then o1.hashCode() == o2.hashCode(). (The reverse is not necessarily true.) The easiest way to implement these is to just compare the fields that define the state of your object: public class Foo { int bar; String bas; public boolean equals(Object o) { if(o instanceof Foo) { Foo other = (Foo)o; return bar == other.bar && bas != null && bas.equals(other.bas); } else { return false; } } public int hashCode() { int hash = 37; hash ^= bar; if(bas != null) { hash ^= bas.hashCode(); } return hash; } } One good way to make this easier is to use the jakarta commons EqualsBuilder and HashCodeBuilder classes. They also help you implement them "well," especially hashCode. GreG --- thomas kukofka <thomaskukofka(a)web.de&gt; wrote: web.de<https://lists.jboss.org/mailman/listinfo/rules-users>