Java taking reference of LinkedList for updations

[Last Samurai]

Hi,

I'm populating a LinkedList of Strings from database. Also Im assigning this list into different objects. when i try to add a new element in the linked list from a particular object, it updates all the objects in which i assigned the list into. Probably it is taking the reference of the list in the objects.

How can i solve this problem. Is there any other way to do it?

Any help is very appreciated.
Thanks in advance

[bhanu chowdary]

Basically you are assigning the same Linkedlist to different variables. Since they all refer to the same object the change will be reflected everywhere.
Use a different linkedlist for the one you are adding.

[Vijay Tidake]

Hi,

Please see code and comments.

import java.util.LinkedList;
import java.util.List;

class Main {
	public static void main(String[] args) {
		List<String> list = new LinkedList<String>();
		list.add("H");
		list.add("E");
		list.add("L");
		list.add("L");
		list.add("0");

		List<String> list1 = list;
		List<String> list2 = list1;

		list2.add(" Java");

		System.out.println(list);

		/*
		 * In above steps you are creating only one object of LinkedList and all
		 * the references list,list1 and list2 are pointing to the same objects
		 * .so if you modify the LinkedList using any one reference the change
		 * is reflected in all references sibce they are all pointing to same
		 * object.
		 */
		List<String> list3 = new LinkedList<String>();
		list3.addAll(list);

		list3.add(" world");

		System.out.println(list);// Original unmodified
		System.out.println(list3);// Modified new list
	}
}

Thanks

[Rob Spoor]

The creation of list3 can be shorter:

List<String> list3 = new LinkedList<String>(list);

Other than that, your code and comments are spot-on.

[Last Samurai]

Thanks a lot for your response. I've implemented it but yet to test!! Will get back in case of any issues.

Thanks again