SelectionKey acceptKey = sc.register(acceptSelector,
SelectionKey.OP_READ, argObj);
assertEquals(sc.keyFor(acceptSelector), acceptKey);
SelectionKey acceptKeyObjNull = sc.register(acceptSelector,
SelectionKey.OP_READ, null);
assertSame(sc.keyFor(acceptSelector), acceptKeyObjNull);
assertSame(acceptKeyObjNull, acceptKey);
SelectionKey acceptKeyOther = sc.register(acceptSelectorOther,
SelectionKey.OP_READ, null);
assertSame(sc.keyFor(acceptSelectorOther), acceptKeyOther);
}