Linkedlist Java

Key facts about Linkedlist
·  LinkedList can have duplicate and null values.·  The LinkedList class implements Queue and Deque interfaces. Therefore, It can also be used as a Queue, Deque or Stack.
·  Java LinkedList is not thread-safe. You must explicitly synchronize concurrent modifications to the LinkedList in a multi-threaded environment.·  Java LinkedList maintains the insertion order of the elements.

Linkedlist Example:import java.util.*;

public class LinkedListExample {

     public static void main(String args[]) {

       /* Linked List Declaration */

       LinkedList<String> testlist = new LinkedList<String>();

       /*add(String Element) is used for adding 

        * the elements to the linked list*/

       testlist.add("Item1");

       testlist.add("Item5");

       testlist.add("Item3");

       testlist.add("Item6");

       testlist.add("Item2");

       /*Display Linked List Content*/

       System.out.println("Linked List Content: " + testlist);

       /*Add First and Last Element*/

       testlist.addFirst("First Item");

       testlist.addLast("Last Item");

       System.out.println("LinkedList Content after addition: " + testlist);

       /*This is how to get and set Values*/

       Object firstvar = testlist.get(0);

       System.out.println("First element: " +firstvar);

       testlist.set(0, "Changed first item");

       Object firstvar2 = testlist.get(0);

       System.out.println("First element after update by set method: " +firstvar2);

       /*Remove first and last element*/

       testlist.removeFirst();

       testlist.removeLast();

       System.out.println("LinkedList after deletion of first and last element: " + testlist);

       /* Add to a Position and remove from a position*/

       testlist.add(0, "Newly added item");

       testlist.remove(2);

       System.out.println("Final Content: " + testlist); 

       /* Access specific element in the Linkedlist*/

       testlist.indexOf(“Newly added item”);

       /*Iterator for Linkedlist*/
       Iterator<String> testlistIterator = testlist.iterator();
        while (testlistIterator.hasNext()) {
            String speciesName = testlistIterator.next();
            System.out.println(speciesName);
        }

Applications of linked list in real world-

1. Image viewer – Previous and next images are linked, hence can be accessed by next and previous button.
2. Previous and next page in web browser – We can access previous and next url searched in web browser by pressing back and next button since, they are linked as linked list.
3. Music Player – Songs in music player are linked to previous and next song. you can play songs either from starting or ending of the list.

AWS Lamdba: Exception in thread "main" java.lang.Error: java.lang.OutOfMemoryError: Metaspace

Execution of newly created Lambda gives below error

Exception in thread "main" java.lang.Error: java.lang.OutOfMemoryError: Metaspace

Bydefault the Memory allocated to Lambda is 128MB this needs to be increased

Solution:









Navigate to your Lambda in AWS and update the Basic setting increase the Memory and test it out