Improve Implementation of Singleton

Design Patterns/src/singleton/SingleObject.java

@@ -2,12 +2,15 @@ package singleton;
 
 public class SingleObject {
 
-    private static final SingleObject instance = new SingleObject();
+    private static SingleObject instance = new SingleObject();
 
     private SingleObject() {
     }
 
     public static SingleObject getInstance() {
+        if (instance == null) {
+            instance = new SingleObject();
+        }
         return instance;
     }