import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
public class Main {
public static void main(String args[]) {
List<Character> list = new ArrayList<Character>();
list.add('X');
System.out.println("Element added to list: " + list.get(0));
Collection<Character> immutableCol = Collections.unmodifiableCollection(list);
immutableCol.add('Y');
}
}
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