Add package demonstrating how to delay code execution in java

core-java-modules/core-java-8-2/src/main/java/com/baeldung/delay/Delay.java

@@ -0,0 +1,95 @@
+package com.baeldung.delay;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
+public class Delay {
+
+    public static void main(String args[]) throws InterruptedException {
+        
+        threadSleep(4, 1);
+
+        timeunitSleep(4, 1);
+
+        delayedServiceTask(5);
+
+        fixedRateServiceTask(5);
+
+        System.out.println("Done.");
+
+        return;
+
+    }
+
+    private static void threadSleep(Integer iterations, Integer secondsToSleep) {
+
+        for (Integer i = 0; i < iterations; i++) {
+
+            System.out.println("This is loop iteration number " + i.toString());
+
+            try {
+                Thread.sleep(secondsToSleep * 1000);
+            } catch (InterruptedException ie) {
+                Thread.currentThread().interrupt();
+            }
+
+        }
+
+    }
+
+    private static void timeunitSleep(Integer iterations, Integer secondsToSleep) {
+
+        for (Integer i = 0; i < iterations; i++) {
+
+            System.out.println("This is loop iteration number " + i.toString());
+
+            try {
+                TimeUnit.SECONDS.sleep(secondsToSleep);
+            } catch (InterruptedException ie) {
+                Thread.currentThread().interrupt();
+            }
+
+        }
+
+    }
+
+    private static void delayedServiceTask(Integer delayInSeconds) {
+
+        final ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
+
+        executorService.schedule(Delay::someTask1, delayInSeconds, TimeUnit.SECONDS);
+
+    }
+
+    private static void fixedRateServiceTask(Integer delayInSeconds) {
+
+        final ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
+
+        ScheduledFuture<?> sf = executorService.scheduleAtFixedRate(Delay::someTask2, 0, delayInSeconds,
+                TimeUnit.SECONDS);
+
+        try {
+            TimeUnit.SECONDS.sleep(20);
+        } catch (InterruptedException ie) {
+            Thread.currentThread().interrupt();
+        }
+
+        sf.cancel(true);
+
+    }
+
+    private static void someTask1() {
+        System.out.println("Task 1 completed.");
+    }
+
+    private static void someTask2() {
+        System.out.println("Task 2 completed.");
+    }
+    
+    public static int main(Boolean isTest) {
+        return 0;
+    }
+
+}

core-java-modules/core-java-8-2/src/test/java/com/baeldung/delay/DelayUnitTest.java

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+package com.baeldung.delay;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class DelayUnitTest {
+
+    @Test
+    void givenMain_returnZero() {
+        assertEquals(Delay.main(true), 0);
+    }
+    
+}