Static Keyword

Posted By on September 16, 2014

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Dynamic Method Dispatch or Run Time Polymorphism
The InstanceOf Keyword

static keyword

The static keyword is used in java mainly for memory management. We may apply static keyword with variables, methods, blocks and nested class. The static keyword belongs to the class than instance of the class.

The static can be:

  1. variable (also known as class variable)
  2. method (also known as class method)
  3. block
  4. nested class

1) static variable

If you declare any variable as static, it is known static variable.
  • The static variable can be used to refer the common property of all objects (that is not unique for each object) e.g. company name of employees,college name of students etc.
  • The static variable gets memory only once in class area at the time of class loading.

Advantage of static variable

It makes your program memory efficient (i.e it saves memory).

Understanding problem without static variable

  1. class Student{
  2.      int rollno;
  3.      String name;
  4.      String college=“ITS”;
  5. }

Suppose there are 500 students in my college, now all instance data members will get memory each time when object is created.All student have its unique rollno and name so instance data member is good.Here, college refers to the common property of all objects.If we make it static,this field will get memory only once.

static property is shared to all objects.

Example of static variable

  1. //Program of static variable
  2. class Student8{
  3.    int rollno;
  4.    String name;
  5.    static String college =“ITS”;
  6.    Student8(int r,String n){
  7.    rollno = r;
  8.    name = n;
  9.    }
  10.  void display (){System.out.println(rollno+” “+name+” “+college);}
  11.  public static void main(String args[]){
  12.  Student8 s1 = new Student8(111,“Karan”);
  13.  Student8 s2 = new Student8(222,“Aryan”);
  14.  s1.display();
  15.  s2.display();
  16.  }
  17. }

Test it Now

Output:111 Karan ITS
       222 Aryan ITS

Static Variable

Dynamic Method Dispatch or Run Time Polymorphism
The InstanceOf Keyword

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Posted by Akash Kurup

Founder and C.E.O, World4Engineers Educationist and Entrepreneur by passion. Orator and blogger by hobby