What is Variable in Java Programming Langauge?

  What is Variable in Java Programming Langauge?

• //Variables:-

• //In java Programming Language Variable is piece of memory used to store the information.
• //One Variable can store One Information at time.
• //Variable also used in information Reuseability.
• //Variable assigned With Datatype.
• //to utilize variable in java programming language we need to follow bellow step:
• //1.Variable Declaration--> Allocating/Reserving Memory.
• //ex. 
• String name; 
• int rollNum; 
• float weight; 
• char gender;
• //2.Variable Initialization-->Assigning/inserting value.
• //ex. 
• name="Sambhaji"; 
• rollNumber=22; 
• weight=52.52f; 
• gender='M';
• //3.usage(Printing/any other Operation)
•  //ex. 
• System.out.println("My Name is "+name);
• System.out.println("My Roll Number is "+rollNumber);
• System.out.println("My Weight is "+weight);
• System.out.println("My Gender is "+gender);
• //Syntax of Variable is---> Datatypes VariableName=Value;
• //for creating variable we need information
• //i.e.information may contain character, digit, mixture of both etc.
• //to store the information we can not declare the variable, we have to declare datatype for it.

                    

• //Types of Variable:-

• //1.Global Variable:

• //It is Declared inside the classbody, but outside the Method/Block/constructor.
• //Scope of Global Variable throughout the class.
• //It is also called Permanent Variable / Instance Variable.
• //This variable can not accessed in static method,but can be accessed in Non static Method within class.
• //Global variable have a default value. 
• for int-->0 , 
• String-->"Null", 
• Boolean="False".

• //2.Local Variable:

• //The Variable which is Declared inside the method/block/constructor is called Local variable
• //The scope of Local Variable Remains Only within the method/block/constructor.
• //It is also called Temporary variable.
• //Local Variable cannot defined with Static Keyword.
• //We can not declare more than one local variable of same Name within the Method.
• //Local variable does not have default value in java. we need to provide the value otherwise it shows error.

• //3.Static Variable:

• //A Variable declared with static keyword is called static variable
• //It is also called class variable.
• //It is declared inside class of body and outside the method body.
• //Static variable can be accessed in both static and non static method.
• //static variable has a default value.
• int-->0 , 
• String-->"Null", 
• Boolean="False".

 

• //Calling Global Variable

• //same class:-

• //Static Variable-->System.out.println("My Sum is "+variableName);
• //non Static Variable-->System.out.println("My Sum is "+ObjectName.variableName);

• //Differnt class:-

• //Static Variable-->System.out.println("My Sum is "+anotherclassName.variableName);
• //non Static Variable-->System.out.println("My Sum is "+ObjectName.variableName);

====================================================================

//Program I:-

package studyOfProject; 

public class StudyOfVariables

{             

    int a=26; // Global Variable

    static int b=55; //static variable

  public static void main(String[] args)

    {

              int x=123; // Local Variable

    }

}

====================================================================