I have a problem with for-loop and if -statement

import java.util.*;

         public class Main 
     {   
       public static void main(String args[]){
         Scanner scan= new Scanner(System.in);   
         User cg = new User("Clarke","griffinc@gmail.com");
         User bb = new User("Bellamy","blakeb@gmail.com");
         User ob = new User("Octavia","blakeo@gmail.com");
         User rr = new User("Raven","reyesr@gmail.com");
         User jm = new User("John","murphyj@gmail.com");
         User mg = new User("Monty","greenm@gmail.com");

         Message message1= new Message("Clarke","Clake :...");
         Message message2= new Message("Bellame","Bellame:...");
         Message message3= new Message("Octavia","Octavia:..");
         Message message4= new Message("Raven","Raven:..");
         Message message5= new Message("John","John:...");
         Message message6= new Message("Monty","Monty:..");




         ArrayList <User> users= new ArrayList<User>();
         ArrayList<Message> message= new ArrayList<Message>();


         users.add(cg);
         users.add(bb);
         users.add(ob);
         users.add(rr);
         users.add(jm);
         users.add(mg);




         message.add(message1);
         message.add(message2);
         message.add(message3);             
         message.add(message4);
         message.add(message5);             
         message.add(message6);  

         users.get(0).writeMessage(message1);

         //login
         boolean login=false;
         User loginUser=new User(" "," ");

             while (login==false){
             for(int j=0; j<users.size(); j++)
             {
                System.out.println(j+1 +":"+ users.get(j).getUsername());
                }
                System.out.println("Give your username:");  
               String username=scan.next();
                for(int i = 0; i < users.size(); i++)
            {
              if(username.equals(users.get(i).getUsername() ) ) {
                 loginUser=users.get(i);
                 login=true;

              }

            }


   }

             //Menu
              System.out.println("You are online!");
              System.out.println("||Menu|| Choose:");
             System.out.println("1 -> For See Your Wall | 2->For See Your 
     Friend Wall ");
    int n =scan.nextInt();
   int choice=0;
   switch(choice){
       case 1:
       for(int z = 0; z < message.size(); z++)
       if(loginUser.getUsername().equals(message.get(z).getUsername() )){
       System.out.println("Your Wall " + loginUser.readMessage() );
    }
       break;
       case 2:
       break;
       case 3:
       break;
    }
}

}

I dont unterstand when I choose 1 for case in switch the program doesnt go inside the loop for or if statement and my program doesnt run.I dont know exactly where is the problem maybe in if statement.