code: private int findInsertIndex(int key, int hash) {
          int index = index(hash);
          final int maxTry = capacity;
          for (int i = 0; i < maxTry; i++) {
              if (slotIsFree(index)) return index;
              index = nextIndex(index);
          }
          throw new IllegalStateException("Free slots expected");
      }
docs: Find slot to inser key-value