Infinite loop in Function* fixed

[ruslansennov]

@danieldietrich please check this test on current branch

private static Function1<Integer, Integer> recurrent1 = (i1) -> i1 <= 0 ? i1 : Function1Test.recurrent2.apply(i1 - 1) + 1;
private static Function1<Integer, Integer> recurrent2 = Function1Test.recurrent1.memoized();

@Test
public void shouldCalculatedRecursively() {
    assertThat(recurrent1.apply(11)).isEqualTo(11);
    assertThat(recurrent1.apply(22)).isEqualTo(22);
}

I believe you'll see infinite loop because of internal architecture of ConcurrentHashMap. We should use java.util.HashMap inside synchronized block...

[danieldietrich]

You're right - I checked it on current branch and it results in an infinite loop. Good finding!