BAEL-1265: Adding jUnit for article

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;
+    }
+}