Программа выполняется но случай переключения не рассматривается я имею в виду что он вообще не выполняется

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import java.util.*;
public class playing_rock_paper_scissors_against_computer{
    public void main(){
        Scanner in=new Scanner(System.in);      
        System.out.println( "please choose difficulty level 'H' for hard, 'M' for medium and 'E' for easy");
        char lev=in.next().charAt(0);
        System.out.println("OK");
        System.out.println("so lets start ROOOOOCK,PAAAAPER,SCISSORS");
        String ch=in.next();
        double n=Math.random();
        String str;
        switch(lev){
        case 'H':
        if(ch=="rock"){
            if(n>=0.41&&n<=0.9){
                System.out.println("Paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose an easier level next time");
               }
            if(n>=0.31&&n<=0.4){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
                
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
        }    
            
            
        
        if(ch=="paper"){
            if(n>=0.41&&n<=0.9){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose an easier level next time");
               }
            if(n>=0.31&&n<=0.4){
                System.out.println("Paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
            else{
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose an easier level next time");
               }
                
        }
        if(ch=="scissors"){
            if(n>=0.41&&n<=0.9){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose an easier level next time");
               }
            if(n>=0.31&&n<=0.4){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
                }
            if(n>=0.0&&n<=0.3){
                System.out.println("paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
                
                }
            else{
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose an easier level next time");
                }
         }
        case 'M':
        if(ch=="rock"){
            if(n>=0.61&&n<=0.9){
                System.out.println("Paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose level easy next time");
               }
            if(n>=0.31&&n<=0.6){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
            else{
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
                
        }
        if(ch=="paper"){
            if(n>=0.61&&n<=0.9){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose level easy next time");
               }
            if(n>=0.31&&n<=0.6){
                System.out.println("Paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.31){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
            else{
                 System.out.println("Paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
        }
        if(ch=="scissors"){
            if(n>=0.61&&n<=0.9){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
                System.out.println("choose level easy next time");
               }
            if(n>=0.31&&n<=0.6){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
            else{
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
                
         }
        case 'E':
        if(ch=="rock"){
            if(n>=0.41&&n<=0.9){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
               }
            if(n>=0.31&&n<=0.4){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
            }
            else{
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
            
        }
        if(ch=="paper"){
            if(n>=0.41&&n<=0.9){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
               }
            if(n>=0.31&&n<=0.4){
                System.out.println("paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
            }
            else{
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
               }
            }    
        if(ch=="scissors"){
            if(n>=0.41&&n<=0.9){
                System.out.println("paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
            if(n>=0.31&&n<=0.4){
                System.out.println("scissors");
                str="scissors";
                System.out.println("computer puts"+str);
                System.out.println("Unfortunately it is a draw");
            }
            if(n>=0.0&&n<=0.3){
                System.out.println("rock");
                str="rock";
                System.out.println("computer puts"+str);
                System.out.println("user loses please try again");
                System.out.println("computer wins");
            }
            else{
                System.out.println("paper");
                str="paper";
                System.out.println("computer puts"+str);
                System.out.println("User wins yayee!!!!");
            }
        }
     }
     
     System.out.println("thanks for playing the game");    
    }}

Что я уже пробовал:

Я пробовал выполнять,но он просто принимает входные данные до тех пор, пока камень, ножницы или бумага не покинут переключатель и не напечатают непосредственно последнее утверждение

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