@Override public void putAll(Map<? extends U2<K0, K1>, ? extends V> map) { if (!(map instanceof U2Map)) { super.putAll(map); return; } @SuppressWarnings("unchecked") U2Map<K0, K1, V> umap = (U2Map<K0, K1, V>)(U2Map)map; m0.putAll(umap.K0Map()); m1.putAll(umap.K1Map()); }