Properly removing an Integer from a List

Question

Here\'s a nice pitfall I just encountered. Consider a list of integers:

List list = new ArrayList();
list.add(5);
list.add(6);         


        

Answer 1

Java always calls the method that best suits your argument. Auto boxing and implicit upcasting is only performed if there's no method which can be called without casting / auto boxing.

The List interface specifies two remove methods (please note the naming of the arguments):

• remove(Object o)
• remove(int index)

That means that list.remove(1) removes the object at position 1 and remove(new Integer(1)) removes the first occurrence of the specified element from this list.