Java: static
The static keyword can be used in three scenarios
- static variables
- static methods
- static blocks of code.
Static variable
A static variable is a variable which belongs to the class and not to object(instance).
Static variables are initialized only once , at the start of the execution . These variables will be initialized first, before the initialization of any instance variables.
A single copy to be shared by all instances of the class.
A static variable can be accessed directly by the class name and doesn't need any object.
Syntax : <class-name>.<variable-name>
Static method
A static methos is a method which belongs to the class and not to the object(instance)
A static method can access only static data. It can not access non-static data (instance variables)
A static method can call only other static methods and can not call a non-static method from it.
A static method can be accessed directly by the class name and doesn't need any object
Syntax : <class-name>.<method-name>
A static method cannot refer to "this" or "super" keywords in anyway
NB main method is static , since it must be be accessible for an application to run , before any instantiation takes place.
Static block
The static block, is a block of statement inside a Java class that will be executed when a class is first loaded in to the JVM
class Test{
static {
//Code goes here
}
}
A static block helps to initialize the static data members, just like constructors help to initialize instance members
