package net.bench.resources.unmodifiable.collection;

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

public class ConvertArrayListToReadOnly {

	public static void main(String[] args) {

		// 1. list of String
		List<String> list = new ArrayList<>();


		// 1.1 add names
		list.add("Woman");
		list.add("Batman");
		list.add("Superman");
		list.add("Spiderman");
		list.add("Human");


		// 1.2 iterating/printing original List
		System.out.println("1. Orginal list : \n");
		list.forEach(System.out::println);


		// 2. convert modifiable list to immutable list
		List<String> unmodifiableList = Collections
				.unmodifiableList(list);


		// 2.1 iterating/printing original List
		System.out.println("\n\n2. Read-only list : \n");
		unmodifiableList.forEach(System.out::println);


		// 3. trying to modify unmodifiable list
		System.out.println("\n\n3. Trying to modify unmodifiable list : \n");
		try {
			unmodifiableList.add("Newman");
		}
		catch(UnsupportedOperationException usopex) {
			System.out.println("In Exception block : ");
			usopex.printStackTrace();
		}
	}
}

1. Orginal list : 

Woman
Batman
Superman
Spiderman
Human


2. Read-only list : 

Woman
Batman
Superman
Spiderman
Human


3. Trying to modify unmodifiable list : 

In Exception block : 
java.lang.UnsupportedOperationException
	at java.util.Collections$UnmodifiableCollection.add(Collections.java:1055)
	at net.bench.resources.unmodifiable.collection.ConvertArrayListToReadOnly
.main(ConvertArrayListToReadOnly.java:41)