underlying procedure for someMethod(SomeClass.class)

in hibernate to create criteria we use

Criteria criterea=session.createCritera(SomeClass.class)

It may be available in some other examples too but I am not able to understand the structure of these type of methods.

NOTE this is an example I am trying to put to understand use of SomeClass.class like arguments

my question here is what is purpose of SomeClass.class ? why do we need it, what is the advantages of using it as argument.