BAEL-2346: modifying concurrency code to add more examples (#5843)

core-java-concurrency/src/main/java/com/baeldung/concurrent/Scheduledexecutorservice/ScheduledExecutorServiceDemo.java

@@ -1,34 +1,52 @@
 package com.baeldung.concurrent.Scheduledexecutorservice;
 
 import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
 
 public class ScheduledExecutorServiceDemo {
 
-	public void execute() {
+	private void execute() {
 		ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
-
+		getTasksToRun().apply(executorService);
-		ScheduledFuture<?> scheduledFuture = executorService.schedule(() -> {
-			// Task
-		}, 1, TimeUnit.SECONDS);
-
-		executorService.scheduleAtFixedRate(() -> {
-			// Task
-		}, 1, 10, TimeUnit.SECONDS);
-
-		executorService.scheduleWithFixedDelay(() -> {
-			// Task
-		}, 1, 10, TimeUnit.SECONDS);
-
-		Future<String> future = executorService.schedule(() -> {
-			// Task
-			return "Hellow world";
-		}, 1, TimeUnit.SECONDS);
-
 		executorService.shutdown();
 	}
 
+	private void executeWithMultiThread() {
+		ScheduledExecutorService executorService = Executors.newScheduledThreadPool(2);
+		getTasksToRun().apply(executorService);
+		executorService.shutdown();
+	}
+
+	private Function<ScheduledExecutorService, Void> getTasksToRun() {
+		return (executorService -> {
+			ScheduledFuture<?> scheduledFuture1 = executorService.schedule(() -> {
+				// Task
+			}, 1, TimeUnit.SECONDS);
+
+			ScheduledFuture<?> scheduledFuture2 = executorService.scheduleAtFixedRate(() -> {
+				// Task
+			}, 1, 10, TimeUnit.SECONDS);
+
+			ScheduledFuture<?> scheduledFuture3 = executorService.scheduleWithFixedDelay(() -> {
+				// Task
+			}, 1, 10, TimeUnit.SECONDS);
+
+			ScheduledFuture<String> scheduledFuture4 = executorService.schedule(() -> {
+				// Task
+				return "Hellow world";
+			}, 1, TimeUnit.SECONDS);
+			return null;
+		});
+	}
+
+	public static void main(String... args) {
+		ScheduledExecutorServiceDemo demo = new ScheduledExecutorServiceDemo();
+		demo.execute();
+		demo.executeWithMultiThread();
+	}
+
+
 }

core-java-concurrency/src/main/java/com/baeldung/concurrent/daemon/MultipleThreadsExample.java

@@ -0,0 +1,12 @@
+package com.baeldung.concurrent.daemon;
+
+public class MultipleThreadsExample {
+    public static void main(String[] args) {
+        NewThread t1 = new NewThread();
+        t1.setName("MyThread-1");
+        NewThread t2 = new NewThread();
+        t2.setName("MyThread-2");
+        t1.start();
+        t2.start();
+    }
+}

core-java-concurrency/src/main/java/com/baeldung/concurrent/daemon/NewThread.java

@@ -1,14 +1,18 @@
 package com.baeldung.concurrent.daemon;
 
 public class NewThread extends Thread {
-
     public void run() {
     	long startTime = System.currentTimeMillis();
         while (true) {
             for (int i = 0; i < 10; i++) {
-                System.out.println("New Thread is running..." + i);
+                System.out.println(this.getName() + ": New Thread is running..." + i);
+                try {
+                    //Wait for one sec so it doesn't print too fast
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
             }
-            
             // prevent the Thread to run forever. It will finish it's execution after 2 seconds
             if (System.currentTimeMillis() - startTime > 2000) {
             	Thread.currentThread().interrupt();

core-java-concurrency/src/main/java/com/baeldung/concurrent/daemon/SingleThreadExample.java

@@ -0,0 +1,8 @@
+package com.baeldung.concurrent.daemon;
+
+public class SingleThreadExample {
+    public static void main(String[] args) {
+        NewThread t = new NewThread();
+        t.start();
+    }
+}