Java way to get a truly immutable copy of a List.

App.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

class App{
  public static void main(String[] args) throws Exception {
		
		List<String> list = Arrays.asList("a", "b", "c");
		List<String> local = new ArrayList<String>(list); 
		List<String> unmodifiableList = Collections.unmodifiableList(local);
		List<String> trulyUnmodifiableList = Collections.unmodifiableList(new ArrayList<String>(local));

		System.out.println("List => "+ list);
		System.out.println("Local => "+ local);
		System.out.println("Unmodifiable => "+ unmodifiableList );
		System.out.println("TrulyUnmodifiableList => "+ trulyUnmodifiableList );

		Collections.reverse(local);
 
		System.out.println("List => "+list);
		System.out.println("Local => "+local);
		System.out.println("Unmodifiable => "+unmodifiableList );
		System.out.println("TrulyUnmodifiableList => "+ trulyUnmodifiableList );
	}
}

result.log

List => [a, b, c]
Local => [a, b, c]
Unmodifiable => [a, b, c]
TrulyUnmodifiableList => [a, b, c]
List => [a, b, c]
Local => [c, b, a]
Unmodifiable => [c, b, a]
TrulyUnmodifiableList => [a, b, c]