Adjust checkstyle rules. Make checkstyle fail the build when violations are found. Correct all current checkstyle violations.

producer-consumer/src/main/java/com/iluwatar/producer/consumer/Producer.java

@@ -19,6 +19,9 @@ public class Producer {
     this.queue = queue;
   }
 
+  /**
+   * Put item in the queue
+   */
   public void produce() throws InterruptedException {
 
     Item item = new Item(name, itemId++);