Spring-beanScope-demo

This demo explain the concept of Singleton.

Main Function:

	//retrieve bean from spring container
	Manager manager = context.getBean("myTeam", Manager.class);
	
	Manager myManager = context.getBean("myTeam", Manager.class);
	
	// check if they are the same
	
	boolean result = (manager == myManager);
			
	// print out the result
	System.out.println("\nPoint to the same object: "+ result);
			
	System.out.println("\nMemory location for theCoach: "+ manager);
			
	System.out.println("\nMemory location for alphaCoach: "+ myManager);

Console output:

Point to the same object: true

Memory location for manager: com.branch.springwork.MarkettingTeam@4e7dc304

Memory location for myManager: com.branch.springwork.MarkettingTeam@4e7dc304

Explanation:

In main function we have defined two Manager object but bot pointing to one memory location. That means there is only one instance has been created for both the manager object. This concept is called Singleton.

Lets examine the beanScope-applicationContext.xml

<bean id="myTeam" class=“com.branch.springwork.MarkettingTeam">

This line is same as

scope=“singleton” is default.

However, when you change scope to prototype then lets see the output:

Console output:

Point to the same object: false

Memory location for theCoach: com.branch.springwork.MarkettingTeam@6895a785

Memory location for alphaCoach: com.branch.springwork.MarkettingTeam@184f6be2

Console output shows that two objects are at different memory location.

Conclusion:

If Spring Bean scope is singleton => Create a single shared instance of the bean. Default scope.

If Spring Bean scope is prototype => Creates a new bean instance for each container request.