Priorityjobscheduler (#3583)

* priority based job execution in java

* minor fixes

* updated to use java 8 features

* fix need for type inference

* handle exception

* indentation

* handling exception generated during terminal of normal flow

* handling exception generated during terminal of normal flow

* added comment

core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/Job.java

@@ -16,7 +16,8 @@ public class Job implements Runnable {
     @Override
     public void run() {
         try {
-            System.out.println("Job:" + jobName + " Priority:" + jobPriority);
+            System.out.println("Job:" + jobName + 
+              " Priority:" + jobPriority);
             Thread.sleep(1000);
         } catch (InterruptedException ignored) {
         }

core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/PriorityJobScheduler.java

@@ -9,21 +9,21 @@ import java.util.concurrent.TimeUnit;
 public class PriorityJobScheduler {
 
     private ExecutorService priorityJobPoolExecutor;
-    private ExecutorService priorityJobScheduler;
+    private ExecutorService priorityJobScheduler = 
-    private PriorityBlockingQueue<Runnable> priorityQueue;
+      Executors.newSingleThreadExecutor();
+    private PriorityBlockingQueue<Job> priorityQueue;
 
     public PriorityJobScheduler(Integer poolSize, Integer queueSize) {
         priorityJobPoolExecutor = Executors.newFixedThreadPool(poolSize);
-        Comparator<? super Job> jobComparator = Comparator.comparing(Job::getJobPriority);
+        priorityQueue = new PriorityBlockingQueue<Job>(queueSize, 
-        priorityQueue = new PriorityBlockingQueue<Runnable>(queueSize, 
+          Comparator.comparing(Job::getJobPriority));
-          (Comparator<? super Runnable>) jobComparator);
 
-        priorityJobScheduler = Executors.newSingleThreadExecutor();
         priorityJobScheduler.execute(()->{
             while (true) {
                 try {
                     priorityJobPoolExecutor.execute(priorityQueue.take());
                 } catch (InterruptedException e) {
+                    // exception needs special handling
                     break;
                 }
             }

core-java-concurrency/src/test/java/com/baeldung/concurrent/prioritytaskexecution/PriorityJobSchedulerUnitTest.java

@@ -30,7 +30,9 @@ public class PriorityJobSchedulerUnitTest {
         // delay to avoid job sleep (added for demo) being interrupted
         try {
             Thread.sleep(2000);
-        } catch (InterruptedException ignored) {
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new RuntimeException(e);
         }
         
         pjs.closeScheduler();