public class J {
    private static final K<String> ka = new K<String>();
    private static final K<String> kb = new K<>();
    private static final K<Integer> kc = new K<>();
    private static final K<Object> kd = new K<Object>();

    private static final K2<String, String> k2a = new K2<String, String>();
    private static final K2<String, String> k2b = new K2<>();
    private static final K2<String, Integer> k2c = new K2<>();
    private static final K2<Integer, String> k2d = new K2<>();
    private static final K2<Object, Object> k2e = new K2<Object, Object>();
}