code: public boolean stem(char[] wordBuffer, int offset, int wordLen) {
  		reset();
  		if (b.length < wordLen) {
  			b = new char[ArrayUtil.oversize(wordLen, NUM_BYTES_CHAR)];
  		}
  		System.arraycopy(wordBuffer, offset, b, 0, wordLen);
  		i = wordLen;
  		return stem(0);
  	}
docs: Stem a word contained in a portion of a char[] array. Returns true if the
  stemming process resulted in a word different from the input. You can
  retrieve the result with getResultLength()/getResultBuffer() or
  toString().