Merge pull request iluwatar#609 from igorcadelima/master

Protect against instantiation via reflection

Author: iluwatar

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

@@ -1,24 +1,20 @@
 /**
- * The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * The MIT License Copyright (c) 2014-2016 Ilkka Seppälä
  *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
+ * associated documentation files (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge, publish, distribute,
+ * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
+ * The above copyright notice and this permission notice shall be included in all copies or
+ * substantial portions of the Software.
  *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
+ * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 package com.iluwatar.singleton;
 
@@ -34,8 +30,10 @@ public final class ThreadSafeLazyLoadedIvoryTower {
   private static ThreadSafeLazyLoadedIvoryTower instance;
 
   private ThreadSafeLazyLoadedIvoryTower() {
-  // to prevent instantiating by Reflection call
-    if (instance != null) {
+    // protect against instantiation via reflection
+    if (instance == null) {
+      instance = this;
+    } else {
       throw new IllegalStateException("Already initialized.");
     }
   }
@@ -44,7 +42,6 @@ private ThreadSafeLazyLoadedIvoryTower() {
    * The instance gets created only when it is called for first time. Lazy-loading
    */
   public static synchronized ThreadSafeLazyLoadedIvoryTower getInstance() {
-
     if (instance == null) {
       instance = new ThreadSafeLazyLoadedIvoryTower();
     }