Java Variables And Data Types

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Data types in every programming language tell what type of values can be stored in a variable. Variables are placeholders that can hold data in a memory location. Two types of data types are available in Java

Primitive data types
Object(reference) data types

Primitive data types

There are 8 primitive data types in Java.

byte

A byte is an 8-bit signed integer
Ranging from -128 to 127
The default value is 0
Example: byte value = 5;

short

short is a 16-bit signed integer
ranging from -32,768 to 32,767
The default value is 0
example: short value = 2500;

int

int is a 32-bit signed integer
Ranging from - 2,147,483,648 to - 2,147,483,647
The default value is 0
Example: int value = 32540785;

long

long is a 64-bit signed integer
Ranging from -9,223,372,036,854,775,808 to -9,223,372,036,854,775,807
The default value is 0L
Example: long value = -250000L

float

float is a 32-bit floating point with precision
The default value is 0.0f
Example: float value = 45.2f;

double

double is a 64-bit floating-point with precision
The default value is 0.0d
Example: double value = 458.23;

boolean

boolean type is a 1-bit information
boolean has two values. true and false
The default value is false
Example:boolean status = true;

char

char is a single 16-bit Unicode character
char data type is used to hold a single character
Example: char value = 'x';

Object(Reference) data types

Object data types represent a variable with its type as an object that is the combination of other object data types and primitive types.

Object types can be created by using the constructors of Java classes.

Object types are used to access properties and methods defined inside a java class.

The The default value of an object type is null.

Example: Car benz = new Car();

Here benz is an object of type Car.

String

String is a reference type that can store character strings. All string literals in Java are the instances of the inbuilt String class

Keep the below points in mind while creating Java variables.

We can create a java variable by using 0-9, A-Z,a-z, _ and $
Variable names must start with a letter,- or $.
Variable names are case-sensitive. name and Name are two different variables.
Java reserved keywords like class, public, int, boolean ... are not allowed to be variable names.

Examples:


        	String name = "John";
        	String name = "John" + " "+"Junior";
        	String name = new String("John Junior")

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