Variables in Java: Local, Instance and Static Variables

Java Programming Course
Start Learning View All CoursesVariables in Java: An Overview
What is a Variable in Java?
Variable Declaration
There are various types of declaration that happen by using Java variables such as
- Strings- which stores text, Such as "Hello world".
- Int- it stores any integer, specifically any whole number without decimal.
- Float- stores "floating point" numbers that include decimal values
- Char- it stores characters such as 'x', and 'y'. It is denoted by single quotes
- Boolean- store values if true or false state.
- datatype: it denotes the types of Data that are going to be stored
- data_name: a particular name of that variable
Example
class Example
{
public static void main ( String[] args )
{
long payAmount = 184; //the declaration of the variable
System.out.println("The variable contains: " + payAmount );
}
}
Output
Long payAmount = 184;
Variable Initialization
- datatype: it defines what type of data is going to be stored in a variable
- variable_name: Particular name of the variable
- value: initially stored value in the variable
Types of Variables in Java

Local variables
- It is created when a block is entered in the storage and then it calls and destroys the block just after exiting from the function.
- It is important to initialize a local variable before using it.
Example
import java.io.*;
class DNT
{
public static void main(String[] args)
{
int var = 89; // Declared a Local Variable
// This variable is local to this main method only
System.out.println("Local Variable: " + var);
}
}
This Java example illustrates the concept of local variables with a scope that is only the main method by declaring and initializing a local variable "var" with the value 89.
Output:
Local Variable: 89
Instance Variables
- An instance variable is created when an object class is generated and it gets destroyed when the same object class is destroyed
- Programmers can use access specifiers for instance variables
- It is not mandatory to initialize instance variables
Example
import java.io.*;
class DNT
{
public String student; // Declared Instance Variable
public DNT()
{ // Default Constructor
this.student= "Urmi Bose"; // initializing Instance Variable
}
//Main Method
public static void main(String[] args)
{
// Object Creation
DNT name = new DNT();
System.out.println("Student name is: " + name.student);
}
}
In this Java example, the class "DNT" contains a declaration for an instance variable named "student" that is initialized in the default constructor to demonstrate the use of instance variables. An object of the class is then constructed to allow access to and printing of the student's name.
Output
Student name is : Urmi Bose
Static variables
- Static variables are declared as instance variables.
- It is created to start the execution of the program and then destroy it automatically after the execution ends.
- It uses static keywords for the declaration of the static variable within a class
Example
import java.io.*;
class DNT
{
public static String student= "Urmi Bose"; //Declared static variable
public static void main (String[] args) {
//student variable can be accessed without object creation
System.out.println("Student Name is : "+DNT.student);
}
}
This Java example prints the value "Urmi Bose" from a static variable named "student" that is declared inside the class "DNT," enabling access by class name simply without creating an object.
Output:
Student Name is: Urmi Bose
FAQs
1. What are the variables in Java?
In Java, variables serve as storage containers for data types like numbers, text, and objects.
2. What are the 3 types of variables in Java?
Local, instance and static variables are the three different categories of variables in Java.
3. What is a variable declaration in Java?
The data type and variable name must be specified when declaring a variable in Java.