Merge pull request iluwatar#583 from shaiktaj/patch-1

iluwatar · web-flow · commit 600553ec0f7d · 2017-08-12T16:58:01.000+03:00
Updated ThreadSafeLazyLoadedivoryTower
diff --git a/singleton/src/main/java/com/iluwatar/singleton/ThreadSafeLazyLoadedIvoryTower.java b/singleton/src/main/java/com/iluwatar/singleton/ThreadSafeLazyLoadedIvoryTower.java
@@ -33,7 +33,12 @@ public final class ThreadSafeLazyLoadedIvoryTower {
 
   private static ThreadSafeLazyLoadedIvoryTower instance;
 
-  private ThreadSafeLazyLoadedIvoryTower() {}
+  private ThreadSafeLazyLoadedIvoryTower() {
+  // to prevent instantiating by Reflection call
+    if (instance != null) {
+      throw new IllegalStateException("Already initialized.");
+    }
+  }
 
   /**
    * The instance gets created only when it is called for first time. Lazy-loading
