In Spring, bean scope is used to decide which type of bean instance should be
return from Spring container back to the caller.

5 types of bean scopes supported :

1. singleton – Return a single bean instance per Spring IoC container
2. prototype – Return a new bean instance each time when requested
3. request – Return a single bean instance per HTTP request. *
4. session – Return a single bean instance per HTTP session. *
5. globalSession – Return a single bean instance per global HTTP session. *

In most cases, you may only deal with the Spring’s core scope – singleton
and prototype , and the default scope is singleton.

http://www.mkyong.com/spring/spring-bean-scopes-examples/