Merge pull request #532 from leogtzr/master

Adding initialization-on-demand idiom and noninstantiable class instead of interface constant idiom

singleton/src/main/java/com/iluwatar/singleton/IvoryTower.java

@@ -27,16 +27,16 @@ package com.iluwatar.singleton;
  */
 public final class IvoryTower {
 
-  /**
-   * Static to class instance of the class.
-   */
-  private static final IvoryTower INSTANCE = new IvoryTower();
-
   /**
    * Private constructor so nobody can instantiate the class.
    */
   private IvoryTower() {}
 
+  /**
+   * Static to class instance of the class.
+   */
+  private static final IvoryTower INSTANCE = new IvoryTower();
+
   /**
    * To be called by user to obtain instance of the class.
    *