Adding ExecutorService files

Java/ExecutorService/ScheduledThreadPoolExecutorExample.java

@@ -0,0 +1,22 @@
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+class RunnableTask implements Runnable{
+    long startTime;
+
+    RunnableTask(){
+        startTime = System.currentTimeMillis();
+    }
+    @Override
+    public void run() {
+        System.out.println("Seconds : "+((System.currentTimeMillis() - startTime)/1000));
+    }
+}
+
+public class ScheduledThreadPoolExecutorExample {
+    public static void main(String[] args) {
+        ScheduledExecutorService executor = Executors.newScheduledThreadPool(2);
+        executor.scheduleWithFixedDelay(new RunnableTask(), 3, 2, TimeUnit.SECONDS);
+    }
+}