JAVA-12045 : move java concurrency ebook content code to common module (#12559)

* JAVA-12045 : move java concurrency ebook content code to common module

* JAVA-12045: addressed the review comments .. renamed package names and placed core-java-concurrency-simple module in pom.xml

* JAVA-12045: removed duplicate module after renaming java-simple-module to core-java-simple-module

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

@@ -1,52 +0,0 @@
-package com.baeldung.concurrent.Scheduledexecutorservice;
-
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
-import java.util.concurrent.TimeUnit;
-import java.util.function.Function;
-
-public class ScheduledExecutorServiceDemo {
-
-	private void execute() {
-		ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
-		getTasksToRun().apply(executorService);
-		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-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/executorservice/DelayedCallable.java

@@ -1,39 +0,0 @@
-package com.baeldung.concurrent.executorservice;
-
-import java.util.concurrent.Callable;
-import java.util.concurrent.CountDownLatch;
-
-public class DelayedCallable implements Callable<String> {
-    
-    private String name;
-    private long period;
-    private CountDownLatch latch;
-    
-    public DelayedCallable(String name, long period, CountDownLatch latch) {
-        this(name, period);
-        this.latch = latch;
-    }
-
-    public DelayedCallable(String name, long period) {
-        this.name = name;
-        this.period = period;
-    }
-
-    public String call() {
-
-        try {
-            Thread.sleep(period);
-            
-            if (latch != null) {
-                latch.countDown();
-            }
-            
-        } catch (InterruptedException ex) {
-            // handle exception
-            ex.printStackTrace();
-            Thread.currentThread().interrupt();
-        }
-
-        return name;
-    }
-}

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/executorservice/ExecutorServiceDemo.java

@@ -1,27 +0,0 @@
-package com.baeldung.concurrent.executorservice;
-
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.TimeUnit;
-
-public class ExecutorServiceDemo {
-
-    ExecutorService executor = Executors.newFixedThreadPool(10);
-
-    public void execute() {
-
-        executor.submit(() -> {
-            new Task();
-        });
-
-        executor.shutdown();
-        executor.shutdownNow();
-        try {
-            executor.awaitTermination(20l, TimeUnit.NANOSECONDS);
-        } catch (InterruptedException e) {
-            e.printStackTrace();
-        }
-
-    }
-
-}

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/executorservice/Task.java

@@ -1,10 +0,0 @@
-package com.baeldung.concurrent.executorservice;
-
-public class Task implements Runnable {
-
-	@Override
-	public void run() {
-		// task details
-	}
-
-}