step4

src/hacker/PoliceThread.java

 package hacker;
 
-public class PoliceThread {
+public class PoliceThread extends Thread{
+    public PoliceThread() {
+        this.setName(this.getClass().getSimpleName());
+    }
+
+
+    public void run() {
+
+        for (int i = 10; i >= 0; i--) {
+
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+           //Prints the remaining time on the screen
+            System.out.println("Police arrive in " + i + " sec");
+        }
+
+         //
+        System.out.println(" Game over for you hackers");
+
+        System.exit(0);
+    }
 }