This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
1. Java does not allow to use pointers so we can never know for sure the memory location of the saving of a static variable
2. static variables are common to all instances of a class, you can consider them to be "global" (with the proper priveledges)
Is global quite the right word for a static variable? It really means a variable which is accessible to (and can be used by) any code anywhere in your application. Global variables are popular in C.
Static fields ought to be restricted to within a class (unless they are final in which case they can be read-only global variables).
Heavy dependency on global variables is a problem in programming; it might create code where changes to global variables can cause nasty errors.