Rule Definition
On large software applications, the number of factory classes can become quite large. There is lot of code duplication because constructors are private and the usage of static methods and variables make the class not extendable. Thus very singleton must re-implement the same basic structure. Spring provides a core factory pattern, which eliminates the need to manually program factory objects (usually realized as singletons). It allows you to decouple the configuration and specification of dependencies from your actual program logic. You will remove the need of your own glue code and gain a much more robust factory implementation with better error handling and fully de-coupled configuration mechanism It will also avoid to fall into the classic double-checked locking issue where you can easily have more than one singleton instance when invoked into a multi-threaded application.

Remediation
Define a factory or singleton using Spring framework

Violation Code Sample

-----> MyInterface.java
interface MyInterface {
  public String getAName();
}
-----> MyConcrete.java
class MyConcrete extends MyInterface {
  public MyConcrete() {
    ...
  }
  public String getAName() {
    ...
  }
}
-----> MyFactory.java
// VIOLATION: the factory pattern is detected
class MyFactory {
  private MyFactory() {
    ...
  }
  public static MyInterface getMyInterface () {
    ...
  }
}
----> Java Client code
MyInterface theInterface = MyFactory.getMyInterface ();
String name = theInterface.getAName();

Fixed Code Sample

----> Spring XML file
// FIXED with Spring
<beans>
     <bean name="theInterface"
          class="MyConcrete">
</beans>

----> Java Client code
InputStream is = new FileInputStream("spring_beans.xml");
BeanFactory factory = new XmlBeanFactory(is);

MyInterface theInterface = (MyInterface) factory.getBean("theInterface");
String name = theInterface.getAName();

http://www.devx.com/Java/Article/21665/1763/page/2 http://www.javapassion.com/j2ee/springhelloworld.pdf http://wiki.java.net/bin/view/Javapedia/Singleton http://java.sun.com/developer/JDCTechTips/2006/tt0113.html#1 http://static.springframework.org/spring/docs/2.0.x/reference/beans.html#beans-factory-scopes-singleton