code: public final void xor(ThreadSafeBitSet other) {
          if (other.size != size) throw new IllegalArgumentException("BitSets must be of equal size");
          for (int i = 0; i < bits.length; i++) {
              bits[i] ^= other.bits[i];
          }
      }
docs: this = this ^ other, bitwise
  
  @param other The bit set to xor with.