java.lang.UnsupportedOperationException at java.util.AbstractList.remove(Unknown Source)

Question

I have tried below code

String s[]={"1","2","3","4"};   Collection c=Arrays.asList(s);   System.out.println(c.remove("1") +"  remove flag");    System.out.println(" collcetion "+c);   

I was getting

Exception in thread "main" java.lang.UnsupportedOperationException   at java.util.AbstractList.remove(Unknown Source)   at java.util.AbstractList$Itr.remove(Unknown Source)   at java.util.AbstractCollection.remove(Unknown Source)   at test.main(test.java:26)   

Can anyone help me to solve this issue?

Answer 1

Easy work around is just to pass in the List into an ArrayList's constructor.

For example:

 String valuesInArray[]={"1","2","3","4"};   List modifiableList = new ArrayList(Arrays.asList(valuesInArray)); System.out.println(modifiableList.remove("1") + "  remove flag");   System.out.println(" collcetion "+ modifiableList);  

Response:

true remove flag

collcetion [2, 3, 4]

Answer 2

Slight correction: no, it's not an unmodifiable Collection. It just doesn't support adding and removing elements, because it is backed by the supplied array and arrays aren't resizeable. But it supports operations like list.set(index, element)