collections.remove()

[Amirtharaj Chinnaraj]

hi guys
i tried this code below

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

System.out.println(" collcetion "+c);
  

but i end up in exception below

 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)
   

i dont know the reason
looking for yopur replies
amir

[Joanne Neal]

It is optional for a class that implements the Collection interface to allow objects to be the removed. If it doesn't want to allow objects to be removed, then it's implementation of the remove method should just throw an UnsupportedOperationException. Obviously the object that Arrays.asList returns has chosen to do this.
[ April 24, 2008: Message edited by: Joanne Neal ]

[Vilmantas Baranauskas]

Arrays.asList(s) returns unmodifiable collection. Therefore you need to use other collection:

    
Collection c= new ArrayList(Arrays.asList(s));
 
or
 
Collection c= new HashSet(Arrays.asList(s));