Java Collections .unmodifiableCollection ( Collection <? extends T> c)
Syntax
Collections.unmodifiableCollection(Collection <? extends T> c) has the following syntax.
public static <T> Collection <T> unmodifiableCollection(Collection <? extends T> c)
Example
In the following code shows how to use Collections.unmodifiableCollection(Collection <? extends T> c) method.
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
//from ww w .ja v a2 s. c om
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);
Collection<Character> immutablelist = Collections.unmodifiableCollection(list);
// try to modify the list
immutablelist.add('Z');
}
}
The code above generates the following result.
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