Ambiguity of Remove Method in Java ArrayList

Question

Generally, the usage of remove method for ArrayList in Java is shown as below:

ArrayList<String> list = new ArrayList<String>();
list.add("abc");
list.add("efg");

list.remove(1);   //Removing the second element in ArrayList.
list.remove("abc");  //Removing the element with the value "abc" in ArrayList.

However, there is situation where overloading doesn't work.

ArrayList<Integer> numbers = new ArrayList<Integer>();

numbers.add(1); numbers.add(2); when I tried to remove the element with value 2. It gives me error:

java.lang.IndexOutOfBoundsException: Index: 2, Size: 2
    at java.util.ArrayList.RangeCheck(ArrayList.java:547)
    at java.util.ArrayList.remove(ArrayList.java:387)

So it looks like when it comes to remove number, I can't remove element with specific value. Because the computer would assume all the integer value as index, not the value of element.

It is a subtle error. Is there any other simple way to delete the element with specific integer value?

@HaoyuChen No problem, glad to help. You may be further interested in reading about widening and boxing in Java method overloading hierarchy. It's a good thing to understand :) — Kon
– Kon, Commented Mar 17, 2015 at 4:56

Kon · Accepted Answer · 2015-03-17 04:52:33Z

6

You need to use an Integer object.

    ArrayList<Integer> numbers = new ArrayList<Integer>();
    numbers.add(5);
    numbers.add(10);
    numbers.remove(new Integer(5));
    System.err.println(numbers);
    //Prints [10]

answered Mar 17, 2015 at 4:52

Kon

10.8k6 gold badges46 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

shikjohari · Accepted Answer · 2015-03-17 04:54:17Z

1

Try remove(new Integer(1). This will work as it ll be a exact match to remove(Object o)

answered Mar 17, 2015 at 4:54

shikjohari

2,28812 silver badges24 bronze badges

Comments

Vladimir Yudin · Accepted Answer · 2023-04-21 07:52:43Z

0

Normally you are not removing a hardcoded number, but a variable value. Therefore it is better to use Integer.valueOf(yourIntVar). This way you use an existing object rather than creating a new one.

edited Apr 21, 2023 at 7:52

answered Apr 21, 2023 at 7:51

Vladimir Yudin

93 bronze badges

Collectives™ on Stack Overflow

Ambiguity of Remove Method in Java ArrayList

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related