Initialisation of a class in OO ABAP

To call a static method , or to access a static attribute outside the class we need to initialize the class. What is the syntax to initialize a class.

Lets take an example:

We have a class in SE24, named zclass1. we have a static method (m1) in that class. Now, to call the method (m1) we use the syntax:

             -- zclass1=>m1.

> My qusetion is how the class zclass1 got initialized in ABAP memory?

> If I create an instance (Object) of a class, a memory is allocated for the object in ABAP memory. How long the ABAP memory will be occupied for that class object?

> What is the difference between memory sharing among Static and Instance components of a class?

Thanks in advance.