Static, it's killing me...

Question

I don't understand why it won't get into my head, but I've never truly understood static and why it should be used. I've even read older posts about it and have read about it in books, but it's not making any sense to me. Right now, if the compiler asks for static, I add it... that's not the proper way to go about it. Can anyone help me? Either point me to an article or explain it in terms I would understand, it's bugging me :) Sorry for the newbie question though, it's who I am.

Answer 1

You can think of static as of shared resources which do not belong to any object you instantiate with 'new' keyword.
If you instantiate 100 object of a class which has one static variable, this one static variable will remain the one and only and will be there even if you don't create any instance of the object.
class MyClass {
static int i;
For all your MyClass object variable i will be all the same. Even if you don't have any MyClass objects around, MyClass.i will be always there.
class MyClass {
void myNotStaticMethod() {
static void myStaticMethod() {
myNotStaticMethod() // NOT OK!
Static method also does not belong to any object. If you call myNotStaticMethod() from myStaticMethod() you would actually try to call this.myNotStaticMethod(). Since myStaticMethod() exists beyond context of any object, 'this' reference does not make any sense, because we don't have any object referenced by 'this'. However, if you still want to perform some actions of your objects in a static method, you can do the following:
static void myStaticMethod(MyClass myClass) {
myClass.myNotStaticMethod() //IT'S OK NOW
Hope this helps.