code: public void xor(BitSet other)
      {
          int newLen = Math.max(wlen, other.wlen);
          ensureCapacityWords(newLen);
  
          long [] thisArr = this.bits;
          long [] otherArr = other.bits;
          int pos = Math.min(wlen, other.wlen);
          while (--pos >= 0)
          {
              thisArr[pos] ^= otherArr[pos];
          }
          if (this.wlen < newLen)
          {
              System.arraycopy(otherArr, this.wlen, thisArr, this.wlen, newLen - this.wlen);
          }
          this.wlen = newLen;
      }
docs: this = this XOR other
  @param other The other bitset.