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

lazy-loading/src/main/java/com/iluwatar/lazy/loading/HolderThreadSafe.java

@@ -10,10 +10,16 @@ public class HolderThreadSafe {
 
   private Heavy heavy;
 
+  /**
+   * Constructor
+   */
   public HolderThreadSafe() {
     System.out.println("HolderThreadSafe created");
   }
 
+  /**
+   * Get heavy object
+   */
   public synchronized Heavy getHeavy() {
     if (heavy == null) {
       heavy = new Heavy();