ConcurrentHashClassMap extends ConcurrentHashMap<Class<? extends T>, T> implements ConcurrentClassMap<T> { @Override public ConcurrentMap<Class<? extends T>, T> map() { return this; } ConcurrentHashClassMap();   ConcurrentHashClassMap(int capacity); @Override ConcurrentMap<Class<? extends T>, T> map();  }
@Test void map() { var map = ConcurrentClassMap.of(1); assertSame(map, map.map()); }
@Test void map() { var proxied = new ConcurrentHashMap<Class<? extends Object>, Object>(0); var map = ConcurrentClassMap.of(proxied); assertSame(proxied, map.map()); }