step1

src/hacker/Vault.java

 package hacker;
 import java.util.Random;
 public class Vault {
-    private int password;
+    private int password; // Private so it cannot be accessed from outside the class
 
     public Vault(){
         Random random = new Random();
         this.password = random.nextInt(10000);
+        //Print the correct password in the terminal in order to ensure as a user that the codes are correct.
         System.out.println(" the correct password:"+this.password);
     }
     public boolean isCorrectPassword(int x){
         try{
             Thread.sleep(5);
         }catch (InterruptedException e){
+            //If an interrupt occurs, we print the error
             e.printStackTrace();
         }
         return x == this.password;