Stacks and Queues using the LinkedList class

import java.util.LinkedList;
import java.util.Scanner;
class LinkedLists{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        LinkedList queue = new LinkedList();
        LinkedList stack = new LinkedList();
        int n;
        while(true){
            System.out.print("\n\n1.Queue 2.Stack 3.Exit: ");
            switch(sc.nextInt()){
                case 1: n = 1;
                    while(n==1){
                        System.out.print("\n1.Enqueue 2.Dequeue 3.Get First 4.Get Last 5.Display 6.Back: ");
                        switch(sc.nextInt()){
                            case 1: System.out.print("Enter a string: ");
                                queue.add(sc.next());
                                break;
                            case 2: if(queue.size() > 0) queue.removeFirst();
                                else System.out.println("Nothing to delete.");
                                break;
                            case 3: System.out.println(queue.getFirst());
                                break;
                            case 4: System.out.println(queue.getLast());
                                break;
                            case 5: for(int i = 0; i < queue.size(); i++)
                                    System.out.print(queue.get(i)+"\t");
                                break;
                            case 6: n=0;
                        }
                    }
                    break;
                case 2: n = 1;
                    while(n==1){
                        System.out.print("\n1.Push 2.Pop 3. Peek 4.Display 5.Back: ");
                        switch(sc.nextInt()){
                            case 1: System.out.print("Enter a string: ");
                                stack.add(sc.next());
                                break;
                            case 2: if(stack.size() > 0) stack.removeLast();
                                else System.out.println("Nothing to delete.");
                                break;
                            case 3: if(stack.size() > 0) System.out.println(stack.getLast());
                                else System.out.println("Can't peek.");
                                break;
                            case 4: for(int i = (stack.size()-1); i >= 0; i--)
                                    System.out.print(stack.get(i)+"\n");
                                break;
                            case 5: n = 0;
                        }
                    }
                    break;
                case 3: return;
            }
        }
    }
}