UnsupportedOperationException while removing or adding elements from List

Problem statement: While running following code, UnsupportedOperationException is thrown both at .add() and .remove() method. What is the problem with the code? List myNewList = Array.asList(someArrayOfLong); myNewList.add(new Long(15)); //add an element in the list. myNewList.remove(0); //remove element from the list at index 0. Solution: By the time you get to the remove(i) statement, list is no longer a java.util.ArrayList. When you call Arrays.asList it does not return a java.util.ArrayList. It returns a java.util.Arrays$ArrayList which is an immutable list. You cannot add to it and you cannot remove from it.
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  1. supriya says:

    i was facing the same problem,”UnsupportedOperationException while removing or adding elements from List.”
    what i did was took the arrays.aslist result in new Arraylist and used addAll method to add in it..then we can perform the add/remove from newly created and populated list.

    //Customer_Orders was converted to list by using Arrays.aslist
    //was giving exception on remove


    //what i did was

    List list1= new ArrayList();
    list1.addAll(Arrays.asList(customer_Orders)) ;

    //perform operation on list1

    • Nasrin says:

      Thanks, this surly helped me.

  2. Max Nanasy says:

    What do you mean by “By the time you get to the remove(i) statement, list is no longer a java.util.ArrayList.”?
    A. It crashes before that line
    B. list was never a java.util.ArrayList

  3. Salim says:

    More easy solution is to replace :
    List myNewList = Array.asList(someArrayOfLong);
    by :
    List myNewList = new ArrayList(Array.asList(someArrayOfLong));
    I think it resoled the problem

  4. sridevi says:

    Thank you so muck your post is resolved my problem

  5. gayatri says:

    i’m getting some exception when doing add operation on Collections.unmodifiableList like unsupported operation.can you pls provide a solution for this?

  6. gayatri says:

    Collections.unmodifiableList(new ArrayList(map.values()))
    getting unsupportedException
    pls help

  7. Nagen Kumar Sahu says:

    Thank You So much for the solution

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