if there is "int i,j;" code in class A , will i,j be initialized as 0 respectively? Yes, type "int" instance variables are initialized to '0' by default.
if i and j are in static method, They will be local variables and will not be initialized by default. If you do not specifically initialize them, you will get a message from the compiler.
or they themsleves are static var,what is the circumstances of their initialization?? They will be initialized to '0' by default.
I suggest you write a short program to
test the initialization of other types of variables like char and double and Object.