Variables in Java

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• Variables are named locations in memory that are used to hold a value that may be modified by the program.

• A variable may take different values at different times during execution.

Syntax for variable declaration :

       DataType Identifier = value (optional);

Example :

int a;
int x = 100;
float f = 2.3f;
etc...

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Types of Variable in Java :

Local Variable

Instance Variables (Non-Static Fields)

Class Variables (Static Fields)

1. Local Variable :
   Local variables are those variables whose scope is local to block.A variable which is declared inside the method is called local variable.

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2. Instance Variables (Non-Static Fields)

   A non-static variable which is declared inside the class but out side of the method is instance variable.

   Non-static fields are also known as instance variables because their values are unique to each instance of a class(object), mean to say that every object has its own separate copy of instance variables..
   

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3. Class Variables (Static Fields)

   A static variable which is declared inside the class is class variable.

   Static variable cannot be local.

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Example :

public class Test{  
 int x = 50;//instance variable
 static int y = 100;//static variable

 void myMethod(){
  int z = 150;//local variable  
  } 
}     

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