step1

src/hacker/AscendingHackerThread.java

+package hacker;
+
+public class AscendingHackerThread {
+}

src/hacker/DescendingHackerThread.java

+package hacker;
+
+public class DescendingHackerThread {
+}

src/hacker/Main.java

+package hacker;
+
+public class Main {
+}

src/hacker/PoliceThread.java

+package hacker;
+
+public class PoliceThread {
+}

src/hacker/Vault.java

+package hacker;
+import java.util.Random;
+public class Vault {
+    private int password;
+
+    public Vault(){
+        Random random = new Random();
+        this.password = random.nextInt(10000);
+        System.out.println(" the correct password:"+this.password);
+    }
+    public boolean isCorrectPassword(int x){
+        try{
+            Thread.sleep(5);
+        }catch (InterruptedException e){
+            e.printStackTrace();
+        }
+        return x == this.password;
+    }
+}