Why this method to remove an occurrence from an ArrayList don't work? (Java)

Question

How do I create a method that satisfies the following conditions?

/* 
 * removes all occurrences (if any) of x in the ArrayList object that the parameter list 
 * is referencing. If there is no occurrence of x then the content of the ArrayList
 * is not altered. 
 */
void removeOccurrences(ArrayList<Integer> list, int x)

NOTE: One may think on an algorithm such as the following:

    for (int i=0; i<list.size(); i++)
        if (list.get(i) == x)
          list.remove(i);

What is wrong with that implementation? – Zarwan Oct 13 '15 at 21:43 — Zarwan, Oct 13 '15 at 21:43
Won't a `ConcurrentModificationException` occur? – budi Oct 13 '15 at 21:44 — budi, Oct 13 '15 at 21:44
No, because there is no `Iterator` involved anywhere. – Tripp Kinetics Oct 13 '15 at 21:45 — Tripp Kinetics, Oct 13 '15 at 21:45

score 1 · Answer 1 · answered Oct 13 '15 at 21:43

1

Try using .equals() instead of ==. == checks whether two references point to the same object. .equals() checks whether two objects represent the same data.

answered Oct 13 '15 at 21:43

Tripp Kinetics

5,178
2
23
37

1

This is not an issue. Since one of the operands is a primitive, `x`, the other operand, an `Integer` value, will be unboxed. – Sotirios Delimanolis Oct 13 '15 at 21:47
Are you sure the `Integer` will be unboxed and not the `int` boxed? – Tripp Kinetics Oct 13 '15 at 21:49
1

[Yes.](http://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1) – Sotirios Delimanolis Oct 13 '15 at 21:50

Why this method to remove an occurrence from an ArrayList don't work? (Java)

1 Answers1