drools-eclipse/org.drools.eclipse/src/main/java/org/drools/eclipse/reteoo/ReteooVisitor.java
private static String dotId(final Object object) {
        return Integer.toHexString( System.identityHashCode( object ) ).toUpperCase();
    }
private static String dotId(final Object object) {
        return Integer.toHexString( System.identityHashCode( object ) ).toUpperCase();
    }
The identity hashCode for the given object is used as its unique DOT
identifier.