Create a read-only list in Java

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Demo {
	public static void main(String args[]) throws Exception {
		List<String>list = new ArrayList<String>();
		list.add("A");
		list.add("B");
		list.add("C");
		list = Collections.unmodifiableList(list);
		// An exception is thrown since its a read-only list now
		list.add("D");
		list.add("E");
		list.add("F");
		System.out.println(list);
	}
}