java - Singleton design pattern vs Singleton beans in Spring container

Question

As we all know we have beans as singleton by default in Spring container and if we have a web application based on Spring framework then in that case do we really need to implement Singleton design pattern to hold global data rather than just creating a bean through spring.

Please bear with me if I'm not able to explain what I actually meant to ask.

Answer 1

A singleton bean in Spring and the singleton pattern are quite different. Singleton pattern says that one and only one instance of a particular class will ever be created per classloader.

The scope of a Spring singleton is described as "per container per bean". It is the scope of bean definition to a single object instance per Spring IoC container. The default scope in Spring is Singleton.

Even though the default scope is singleton, you can change the scope of bean by specifying the scope attribute of <bean ../> element.

<bean id=".." class=".." scope="prototype" />