Error while trying to remove a string from an array list of strings

Question

This link says that I can remove a string by directly addressing it with the parameter, like:

myList.remove("myString");

but trying to do this I get the java.lang.UnsupportedOperationException exception.

UPDATE The code I use to create and fill the list:

List<String> myList = new ArrayList<>(myArray.length);
for (String str : myArray) {
    myList.add(str);
}

The code I get the exception while executing:

if (myList.contains("specificString"))
    myList.remove("specificString");
}

How can I remove this element then without using the for loop or an index?

your heading and question are different. You have stated about an exception that occurred but you have questioned about explanation of a java method. — Blip, Apr 30 '15 at 11:28
how is you list created? you could run into this problem: http://stackoverflow.com/a/2965808/421749 — astuetz, Apr 30 '15 at 11:30
Paste the code from create to remove where it get exception. — Mohan Raj, Apr 30 '15 at 11:44
@ArthurEirich i think that it should be `myList` instead of `colourUsedList` — Blip, Apr 30 '15 at 12:12

score 1 · Accepted Answer · answered Apr 30 '15 at 11:33

Assuming yours a ArrayList, ideally you could remove the object from a list using the list.remove(obj) as you did unless the list is unmodifiable as shown below:

    List<String> list = new ArrayList<String>();
    list.add("a");
    list.add("b");
    list.add("c");
    System.out.println(list); // [a,b,c]

    list.remove("a");
    System.out.println(list); // [b,c]

    List<String> unmodifiable = Collections.unmodifiableList(list);
    unmodifiable.remove("b"); // UnsupportedOperationException

score 0 · Answer 2 · answered Apr 30 '15 at 11:33

The List interface (java.util.List) includes a method remove(object). Not all implementations support that method though. For implementations that don't implement this method you get this exception. It is even documented here:

https://docs.oracle.com/javase/7/docs/api/java/util/List.html#remove(java.lang.Object)

If you use ArrayList then you should be fine. If you use some custom fixed size implementation or some other implementation that doesn't suppor that operation then you cannot use this method.

Error while trying to remove a string from an array list of strings

2 Answers2