Check JVM runtime compiler by VisualVM

One of my friends asked me how to determine what kind of runtime compiler of a JVM is using, the 'Server' or 'Client'?

there is some default value listed on Ergonomics, but if you want to make sure of it on your server?

It is not that hard to check, the easier way is to use VisualVM on Overview tab:

Usually, you had better add "-server" parameter to ensure a server mode on your machine.