code: public final int put(Object key, int value, boolean isReplace)
      {
          int prime = _prime;
          int hash = hashCode(key) % prime;
          // int hash = key.hashCode() % prime;
  
          Object[] keys = _keys;
  
          while (true) {
              Object testKey = keys[hash];
  
              if (testKey == null) {
                  keys[hash] = key;
                  _values[hash] = value;
  
                  _size++;
  
                  if (keys.length <= 4 * _size)
                      resize(4 * keys.length);
  
                  return NULL;
              }
              else if (key != testKey) {
                  hash = (hash + 1) % prime;
  
                  continue;
              }
              else if (isReplace) {
                  int old = _values[hash];
  
                  _values[hash] = value;
  
                  return old;
              }
              else {
                  return _values[hash];
              }
          }
      }
docs: Puts a new value in the property table with the appropriate flags