Static means it belongs to the class, not an instance.
If I have a class called Animals with a static variable called legs, I can make 20 instances of Animals but the legs aren't unique to each one. Give the following a try...
We created 3 different TestStatic instances, but changing the value in the 3rd TestStatic object also affected 1 and 2. This should illustrate it.
The very existence of flamethrowers proves that at some time, some where, some place, someone once said to themselves "I'd really like to set those people on fire over there, but I just can't get close enough".
in the above line it looks that you are using the object ob to call the static method. But actually behind the scenes, the class itself is being used to invoke the static method. the convention you used to call the method is allowed but not recommended.