code: @Override
  	public boolean getThenSetBit(int index, boolean value) {
  		index = adjIndex(index);
  		checkMutability();
  
  		int i = index >> ADDRESS_BITS;
  		int m = 1 << (index & ADDRESS_MASK);
  		boolean v = (bits[i] & m) != 0;
  		if (value) {
  			bits[i] |= m;
  		} else {
  			bits[i] &= ~m;
  		}
  		return v;
  	}
docs: accelerators