Tutorial 30 : Static Member in Java смотреть онлайн

In Java, a static member is a member of a class that isn’t associated with an instance of a class. Instead, the member belongs to the class itself. As a result, you can access the static member without first creating a class instance.

The two types of static members are static fields and static methods
In Java, if a field is declared static, then exactly a single copy of that field is created and shared among all instances of that class. It doesn't matter how many times we initialize a class; there will always be only one copy of static field belonging to it. The value of this static field will be shared across all object of either same of any different class.
Similar to static fields, static methods also belong to a class instead of the object, and so they can be called without creating the object of the class in which they reside. They're meant to be used without creating objects of the class.
PROGRAM :
package StaticProgram;

public class Main {

public static void main(String[] args) {
//Java Program to demonstrate the use of static keyword
Student.age=3;
System.out.println(Student.age);
Student.change_name();
Student s1 = new Student();
Student s2 = new Student();
s1.rollno=1;
s1.display();
s2.rollno=2;
s2.display();
}
}
package StaticProgram;

public class Student {
int rollno;//instance variable
static int age;
static String name= "avni";// static variable
static void change_name(){
name="joy";
}
Student(){
System.out.println("this is constructor");
}
//method to display the values
void display (){System.out.println(rollno+" "+name);}
static{System.out.println("static block is invoked");}
}
}