if we need to execute class level one time execution code,then use static blocks and without creation of object we need to perform some task,then go for static methods. If we want variables those values will not be changed from object to anther object,then go for static variables...(According to my knowledge)

Basically static means that there will only be only one instance of that object (the object that is declared static) in the class. If an object is not declared static a new copy of that object is made for every instance of the class that is initialized. Another thing about static objects is that you can call them directly without having to initialize the class at all, which is why if you declare the function main as static then java does not have to initialize the object at all to access the entry point (main function)