static method vs instance method

[rahman habib]

What is difference between static method and instance method.
which one one is better in terms of memory and performance.

[Campbell Ritchie]

Static methods have nothing to do with performance or memory management. They affect different things. A static member:

Is typed by the compiler

Is not polymorphic

Cannot be overridden, only hidden

Belongs to the class, not the object

There is only one copy of it per class

Every object of that class has access to the same static member

Static methods cannot access instance methods or instance fields.

[camilo lopes]

all depend on of the your objective, but static method, this pertence the class and instance method pertence the an object, this do not have relation with a class.
in terms of perfomance nothing change.