Java Collections .unmodifiableList ( List <? extends T> list)
Syntax
Collections.unmodifiableList(List <? extends T> list) has the following syntax.
public static <T> List <T> unmodifiableList(List <? extends T> list)
Example
In the following code shows how to use Collections.unmodifiableList(List <? extends T> list) method.
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/*from w w w . ja v a 2s . c o m*/
public class Main {
public static void main(String[] args) {
// create array list
List<Character> list = new ArrayList<Character> ();
// populate the list
list.add('X');
list.add('Y');
System.out.println("Initial list: "+ list);
// make the list unmodifiable
List<Character> immutablelist = Collections.unmodifiableList(list);
// try to modify the list
immutablelist.add('Z');
}
}
The code above generates the following result.
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