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Sunday 27 January 2013

difference|between static and|vs non static|instance variables|methods|data members in java with example synchronization


static vs non static methods static vs non static data members static and non static data members static and non static methods static and non static variables difference between static and non static variables in java
difference between static and non static variables in java with example static and non static variables in java example difference between static method and instance method in java static and instance methods in java
difference between static and instance methods in java static method vs instance method in java static and instance methods in java synchronization of static and instance methods in java static and instance variables in java with example static and instance variables in java example static vs instance methods in java static vs instance methods in java with example differnece between static and instance methods in java with example differnece between static and instance methods in java example


Static Data members (Methods and variables)   Vs   Non Static or Instance Data members (Methods and variables):

Instance or Non static Data members(Methods and variables):

  Instance or Non – static variable is without the static keyword means that it is part of an object or it also called "instance" and not a part of a class. It is referred to by the name of the specific object to which the method or variable belongs.
1)  Instance variables are those whose memory space is created each and every time whenever object is created.
2)  Instance variable’s are always used for storing specific values.
3)  Programmatically Instance variable’s declaration should not preceded by static keyword.
Syntax:
 Datatype v1,v2…..vn;
4)  Each and every instance variable must be accessed w.r.t object name.
Objectname.Instancedatamembername;
5)  Each and every value of instance variable is not sharable.

     Static Data members(Methods and variables):

Static data members of class in which the concept of static has to do with whether something is part of a class or an object (instance).
    In the case of the main method which is declared as static, it says that the main method is an class method.
   A method that is part of a class, not part of an object. This means that another class could call a class method of another class, by referring to the Class Name method.

1)  Static data members are those whose memory space is creating only once whenever the class is loaded into main memory irrespective of number of objects is created.
2)  Static data members are always used for storing common values.
3)  Programmatically static data members declaration must be preceded by static keyword.
Syntax :
  Static dataype v1,v2……vn;
4)   Each and every static data member must be accessed w.r.t class name.
               Classname.staticdatamembername;
5)  Each and every value of static data member is sharable

The Following Program illustrate the concept of Static and Non static Data members:
  
  // StaticInstanceDemo.java
  
     Class StaticInstanceDemo
   {
      int x=10;   // Instance or non – static data members
      static int y=100;// static data member
      void f1()   // Instance or non – static data members
    {
     System.out.println(“this is f1() function”);
    StaticInstanceDemo.f2();// calling static method from non
                                          // - static context.
    }
static void f2()
{
  // System.out.println(“value of x”+obj.x); Cannot
// non static from static context. error
System.out.println(“this is f2() function”);
}
   public static void main(String args[])
  {
    InstanceDemo obj=new InstanceDemo(); //creation of    
         //object or reference for Non-static //member
    obj.f1();
    StaticInstanceDemo.f2();
  }
}

Analysis: 
     From the above program which illustrates both static and non static such that x and f1() is instance data members and they can be accessed by using object or instance, y and f2() is static data members, they can be accessed by using class name.






3 comments:

  1. Hi, its good to red this blog easy explanations of static and non static variables .

    Thanks for your efforts .
    To know more about statics which should be used when you don't want to have varying behavior for different objects.

    http://efectivejava.blogspot.in/2013/08/when-to-use-static-members-in-java.html



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