Datatypes and Variables in Java

Datatype is the type of data that is to be stored in a program. It says the compiler how much memory need to be allocated for storing values based on type. It is used to reserve a memory in RAM for storing values.

datatype variable_name;

Without declaring a variable i.e specifying a datatype, a variable cannot store value.

Variables in Java

Variable is a name of the reserved storage address which holds a value. To store a value we should first declare a variable.

Below is the way of declaration of variable.

datatype variable_name;

To assign a value to the variables we can use like this below. This is said as initialization.

variable_name = value;

Both initialization and declaration can also be done in one line like below.

datatype variable_name = value;


public class VariableTest {

public static void main(String args[]) {

int a_value=5;




Try In Editor

We should follow the rules and conventions for naming a variables which will be discussed in next topic.

What is a variable or datatype and why they are used detailly ?