In this tutorial, you will learn about Java Variables and Datatypes. Java Variables has three type: instance, local, static(class variable).

Java Variables and Data Types

What is Variable

Variable is a name of the memory address(part of the memory) and it is used to store data of various data types. Each Variable must have a unique name to identify the memory address.

Type of Java Variables

there are mainly four types of variables but here you will learn only three types:

  • Instance
  • Local
  • Static(class Variable)

1. Instance Variable

A variable that is declared outside the method but inside the class is called instance variable.

2. Local Variable

A variable that is declared inside the method is called local variable.

3. Static Variable

A variable which is declared as static is called a static variable and it is also known as the class variable.

Declaration of Java Variables

Here you will learn how to declare java variables and assign the value. Syntax:

type variable_name=value;

java variables Example

Here we are taking two variables num and number where num is int type and number is float type. Example:

int num =5;
float number=10.0;

Let’s see this example where we are using all the java variables type to demonstrate how it works. Example:

class A{
int speed = 45; //instance variable
static int rollno = 888; //static variable
void test()
{
float time = 10.00; //local variable
}
}

Here, speed is an instance variable of int type and it is containing value is 45 and Another variable isroll_no with value 888.

Java Data Types

A data type defines which type of data a variable can store and it has a special name such as int, boolean, float, etc. Java data type has two types: primitive or non-primitive

Primitive Data Types

There are 8 types of the primitive data type in Java:

  • boolean
  • byte
  • short
  • int
  • long
  • double
  • float
  • char
Data Type Default Size Default Value
boolean 1 bit false
byte 1 byte 0
short 2 bytes 0
int 4 bytes 0
long 8 bytes 0L
double 8 bytes 0.0d
float 4 bytes 0.0f
char 2 bytes ‘\u0000’