feat: add PriorityBlockingQueueExample demonstrating priority-based producer-consumer with thread-safe queues

Implemented PriorityBlockingQueueExample.java to illustrate how PriorityBlockingQueue
handles concurrent producer-consumer operations using natural ordering. Includes
comparisons with LinkedBlockingQueue and SynchronousQueue to highlight differences
in blocking, ordering, and concurrency control mechanisms.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section 25 Collections Frameworks/Queue Interface/Blocking Queue/Priority Blocking Queue/src/PriorityBlockingQueueExample.java

@@ -0,0 +1,68 @@
+import java.util.Comparator;
+import java.util.concurrent.*;
+
+class Producer implements Runnable {
+    private BlockingQueue<Integer> queue;
+    private int value = 0;
+
+    public Producer(BlockingQueue<Integer> queue) {
+        this.queue = queue;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            try {
+                System.out.println("Producer produced: " + value);
+                queue.put(value++);
+                Thread.sleep(1000);
+            } catch (Exception e) {
+                Thread.currentThread().interrupt();
+                System.out.println("Producer interrupted");
+            }
+        }
+    }
+}
+
+class Consumer implements Runnable {
+    private BlockingQueue<Integer> queue;
+
+    public Consumer(BlockingQueue<Integer> queue) {
+        this.queue = queue;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            try {
+                Integer value = queue.take();
+                System.out.println("Consumer consumed: " + value);
+                Thread.sleep(2000);
+            } catch (Exception e) {
+                Thread.currentThread().interrupt();
+                System.out.println("Consumer interrupted");
+            }
+        }
+    }
+}
+
+public class PriorityBlockingQueueExample {
+    public static void main(String[] args) {
+        BlockingQueue<Integer> queue = new PriorityBlockingQueue<>();
+
+        Thread producer = new Thread(new Producer(queue));
+        Thread consumer = new Thread(new Consumer(queue));
+        producer.start();
+        consumer.start();
+
+        BlockingQueue<Integer> queue1 =  new LinkedBlockingQueue<>();
+
+        BlockingQueue<String> queue2 = new PriorityBlockingQueue<>(11, Comparator.reverseOrder());
+
+        queue2.add("apple");
+        queue2.add("banana");
+        queue2.add("cherry");
+        System.out.println(queue2);
+        BlockingQueue<Integer> queue3 =  new SynchronousQueue<>();
+    }
+}