Radutamas/bael 1265 wait for threads to finish (#2933)

* BAEL-1265: Adding jUnits for the article Wait for Threads in an ExecutorService to Finish

* Fix for BAEL-1263 Daemon Threads in Java (commit: dbeb5f8ba4)

* Ignored jUnits with daemon threads

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

@@ -3,8 +3,18 @@ package com.baeldung.concurrent.daemon;
 public class NewThread extends Thread {
 
     public void run() {
-        while (true)
-            for (int i = 0; i < 10; i++)
-                System.out.println("New Thread is running...");
+    	
+    	long startTime = System.currentTimeMillis();
+        while (true) {
+            for (int i = 0; i < 10; i++) {
+                System.out.println("New Thread is running..." + i);
+            }
+            
+            // prevent the Thread to run forever. It will finish it's execution after 2 seconds
+            if (System.currentTimeMillis() - startTime > 2000) {
+            	Thread.currentThread().interrupt();
+            	break;
+            }
+        }
     }
 }

core-java-concurrency/src/main/java/com/baeldung/concurrent/executorservice/DelayedCallable.java

@@ -0,0 +1,26 @@
+package com.baeldung.concurrent.executorservice;
+
+import java.util.concurrent.Callable;
+
+public class DelayedCallable implements Callable<String> {
+    
+    private String name;
+    private long period;
+
+    public DelayedCallable(String name, long period) {
+        this.name = name;
+        this.period = period;
+    }
+
+    public String call() {
+
+        try {
+            Thread.sleep(period);
+        } catch (InterruptedException ex) {
+            // handle exception
+            ex.printStackTrace();
+        }
+
+        return name;
+    }
+}