Why there are two 'run as maven build' options in Spring tool suite

I am trying my hands on Spring tool suite. I obs开发者_Python百科erved that it when you right click on your spring project and select run as then there are many options available out which two are

7 Maven build Alt+Shift+X,M

8 Maven build..

For me it look like one and the same thing. Still I am not able to figure out the difference between it.

The first one lets you pick an existing Maven launch configuration. The one with the ... opens a new launch configuration.