help me understand and walk through this task. using java please thanks

App class is

package main; public class App { public void run() { // TODO: code this run so that it works as shown in the example // output in the instructions - and so that all the tests in MainTests pass as well } private void displayInstructions() { System.out.println("Hi! I'm the Two-Ended List app!"); System.out.println( "Every word you enter on a line will be added to me in alternating head/tail order."); System.out.println("I will turn each word to lowercase before it is added."); System.out.println(); System.out.println("I will show you my contents after every word."); System.out.println("I will stop when you enter an empty line."); System.out.println("Ready? Start entering words!"); }

The main class is :

package main; public class Main { public static void main(String[] args) { App app = new App(); app.run(); } }

introduction:

You're going to be making a TwoEndedSll class, representing a singly-linked list that has some specific properties. Here are the details: it will be generic...so you can toss whatever reference type you want in it. you can both add and remove from this list - but only at its head or tail - no adding/removing middle bits! (this is a blessing, of course) if you attempt to remove from an empty list, it'll throw a NoSuchElementException. even though we can add/remove from either end of this list, when we get its contents, they are always in order from head to tail. you should make your Node class a static member class. What does that mean? It should be located inside your TwoEndedSll class and declared as private static Node. Of course, I realize I can't force you to do so. But still...practice good practice, folks! Of the three drills in this checkpoint, this will easily take the longest to complete. But there's an upside: the list you create in this drill makes the other two drills a snap, so the time you spend here will pay off.

Create a TwoEndedSll class in the main package. This class represents a list that you modify and its behaviour is described in the Preamble: if all the TwoEndedSll tests pass, consider that puppy done! Complete the App.java run method so that when you run Main.java, the program behaves as expected by the MainTests. I've added a useful method in App.java that removes some of the drudgery.

1 package main; 2 3 public class Main { 4 5 public static void main(String[] args) { App app = new App(); app.run(); } 7 09 9 } You're going to be making a Two Endedsli class, representing a singly-linked list that has some specific properties. Here are the details: it will be generic...so you can toss whatever reference type you want in it. you can both add and remove from this list - but only at its head or tail - no adding/removing middle bits! (this is a blessing, of course) if you attempt to remove from an empty list, it'll throw a NoSuchElementException. even though we can add/remove from either end of this list, when we get its contents, they are always in order from head to tail. you should make your Node class a static member class. What does that mean? It should be located inside your Two Endedsii class and declared as private static Node. Of course, I realize I can't force you to do so. But still...practice good practice, folks! Of the three drills in this checkpoint, this will easily take the longest to complete. But there's an upside: the list you create in this drill makes the other two drills a snap, so the time you spend here will pay off. 1 package main; 2 3 public class App { 4 5 public void run() { 7 // TODO: code this run so that it works as shown in the example output in the instructions - and so that all the tests in MainTests pass as well 8 9 10 } 11 12 13 private void display Instructions() { System.out.println("Hi! I'm the Two-Ended List app!"); System.out.println( "Every word you enter on a line will be added to me in alternating head/tail order."); System.out.println("I will turn each word to lowercase before it is added."); 15 16 17 18 System.out.println(); 19 20 System.out.println("I will show you my contents after every word."); System.out.println("I will stop when you enter an empty line."); 21 22 23 System.out.println("Ready? Start entering words!"); 24 } 25 } 1. Create a TwoEndedsll class in the main package. This class represents a list that you modify and its behaviour is described in the Preamble: i. if all the Two Endedsil tests pass, consider that puppy done! 2. Complete the App.java run method so that when you run Main.java , the program behaves as expected by the MainTests. i. I've added a useful method in App.java that removes some of the drudgery