Thread-safe Singleton class

New Singleton class name has renamed to ThreadSafeLazyLoadedIvoryTower
and called it from App.java

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

@@ -0,0 +1,23 @@
+package com.iluwatar;
+
+/**
+ *
+ * Thread-safe Singleton class.
+ *
+ */
+public class ThreadSafeLazyLoadedIvoryTower {
+
+	private static ThreadSafeLazyLoadedIvoryTower instance = null;
+
+	public synchronized static ThreadSafeLazyLoadedIvoryTower getInstance() {
+		/*
+		 * The instance gets created only when it is called for first time.
+		 * Lazy-loading
+		 */
+		if (instance == null) {
+			instance = new ThreadSafeLazyLoadedIvoryTower();
+		}
+
+		return instance;
+	}
+}