[JAVA-13957] Added example for Timer functionality (#12906)

Co-authored-by: panagiotiskakos <panagiotis.kakos@libra-is.com>

core-java-modules/core-java-concurrency-simple/src/main/java/com/baeldung/concurrent/startathread/TimerDemoExample.java

@@ -0,0 +1,39 @@
+package com.baeldung.concurrent.startathread;
+
+import java.util.Date;
+import java.util.Timer;
+import java.util.TimerTask;
+
+public class TimerDemoExample {
+
+    private void scheduleOnce() {
+        TimerTask task = new TimerTask() {
+            public void run() {
+                System.out.println("Task performed on: " + new Date() + "\n" + "Thread's name: " + Thread.currentThread()
+                    .getName());
+            }
+        };
+        Timer timer = new Timer("Timer");
+        long delay = 1000L;
+        timer.schedule(task, delay);
+    }
+
+    private void scheduleRecurrently() {
+        TimerTask task = new TimerTask() {
+            public void run() {
+                System.out.println("Recurrent Task performed on: " + new Date() + "\n" + "Thread's name: " + Thread.currentThread()
+                    .getName());
+            }
+        };
+        Timer timer = new Timer("Timer");
+        long delay = 1000L;
+        final long period = 1000L;
+        timer.scheduleAtFixedRate(task, delay, period);
+    }
+
+    public static void main(String[] args) {
+        TimerDemoExample timerDemoExample = new TimerDemoExample();
+        timerDemoExample.scheduleOnce();
+        timerDemoExample.scheduleRecurrently();
+    }
+}