adding code for BAEL-1262 (#2866)

* adding code for BAEL-1262

* fixing the build issue by moving the test to test folder

core-java-concurrency/src/test/java/com/baeldung/concurrent/runnable/RunnableVsThreadTest.java

@@ -0,0 +1,110 @@
+package com.baeldung.concurrent.runnable;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import org.apache.commons.lang3.RandomUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class RunnableVsThreadTest {
+
+	private static Logger log = 
+	  LoggerFactory.getLogger(RunnableVsThreadTest.class);
+
+	@Test
+	public void givenARunnable_whenRunIt_thenResult() throws Exception{
+		Thread thread = new Thread(new SimpleRunnable(
+		  "SimpleRunnable executed using Thread"));
+		thread.start();
+		thread.join();
+		
+		ExecutorService executorService = 
+		  Executors.newCachedThreadPool();
+		
+		executorService.submit(new SimpleRunnable(
+		  "SimpleRunnable executed using ExecutorService")).get();
+		
+		executorService.submit(()-> 
+		  log.info("Lambda runnable executed!!!")).get();
+		executorService.shutdown();
+	}
+	
+	@Test
+	public void givenAThread_whenRunIt_thenResult() throws Exception{
+		Thread thread = new SimpleThread(
+		  "SimpleThread executed using Thread");
+		thread.start();
+		thread.join();
+		
+		ExecutorService executorService = 
+		  Executors.newCachedThreadPool();
+		executorService.submit(new SimpleThread(
+		  "SimpleThread executed using ExecutorService")).get();
+	}
+	
+	@Test
+	public void givenACallable_whenRunIt_thenResult() throws Exception {
+		ExecutorService executorService = 
+		  Executors.newCachedThreadPool();
+		
+		Future<Integer> future = executorService.submit(new SimpleCallable());
+		log.info("Result from callable: {}", future.get());
+		
+		future = executorService.submit(() -> {
+		  return RandomUtils.nextInt(0, 100);
+		}); 
+		log.info("Result from callable: {}", future.get());
+
+	}
+}
+
+class SimpleThread extends Thread{
+	
+	private static final Logger log = 
+	  LoggerFactory.getLogger(SimpleThread.class);
+	
+	private String message;
+	
+	public SimpleThread(String message) {
+		this.message = message;
+	}
+	
+	@Override
+	public void run() {
+		log.info(message);
+	}
+}
+
+class SimpleRunnable implements Runnable {
+
+	private static final Logger log = 
+	  LoggerFactory.getLogger(SimpleRunnable.class);
+	
+	private String message;
+	
+	public SimpleRunnable(String message) {
+		this.message = message;
+	}
+	
+	
+	@Override
+	public void run() {
+		log.info(message);
+	}
+}
+
+class SimpleCallable implements Callable<Integer> {
+
+	@Override
+	public Integer call() throws Exception {
+		return RandomUtils.nextInt(0, 100);
+	}
+
+}