code: public void clear(final boolean shrink) {
  		while (queue.poll() != null) {
  			;
  		}
  		if (elementCount > 0) {
  			elementCount = 0;
  		}
  		if (shrink && (elementData.length > 1024) && (elementData.length > defaultSize)) {
  			elementData = newElementArray(defaultSize);
  		} else {
  			Arrays.fill(elementData, null);
  		}
  		computeMaxSize();
  		while (queue.poll() != null) {
  			;
  		}
  	}
docs: Clear the set
  
  @param shrink if true, shrink the set to initial size