public boolean equals(Object obj) {
        if (obj == this) {
            return true;      
        }
        if (!(obj instanceof KeyToGroupMap)) {
            return false;
        }
        KeyToGroupMap that = (KeyToGroupMap) obj;
        if (!ObjectUtilities.equal(this.defaultGroup, that.defaultGroup)) {
            return false;
        }
        if (!this.keyToGroupMap.equals(that.keyToGroupMap)) {
            return false;
        }
        return true;