Tutorials References Exercises Videos Menu
Free Website Get Certified Upgrade

Java Tutorial

Java HOME Java Intro Java Get Started Java Syntax Java Output Java Comments Java Variables Java Data Types Java Type Casting Java Operators Java Strings Java Math Java Booleans Java If...Else Java Switch Java While Loop Java For Loop Java Break/Continue Java Arrays

Java Methods

Java Methods Java Method Parameters Java Method Overloading Java Scope Java Recursion

Java Classes

Java OOP Java Classes/Objects Java Class Attributes Java Class Methods Java Constructors Java Modifiers Java Encapsulation Java Packages / API Java Inheritance Java Polymorphism Java Inner Classes Java Abstraction Java Interface Java Enums Java User Input Java Date Java ArrayList Java LinkedList Java HashMap Java HashSet Java Iterator Java Wrapper Classes Java Exceptions Java RegEx Java Threads Java Lambda

Java File Handling

Java Files Java Create/Write Files Java Read Files Java Delete Files

Java How To

Add Two Numbers Count Words Reverse a String

Java Reference

Java Keywords Java String Methods Java Math Methods

Java Examples

Java Examples Java Compiler Java Exercises Java Quiz Java Certificate


Java Data Types


Java Data Types

As explained in the previous chapter, a variable in Java must be a specified data type:

Example

int myNum = 5;               // Integer (whole number)
float myFloatNum = 5.99f;    // Floating point number
char myLetter = 'D';         // Character
boolean myBool = true;       // Boolean
String myText = "Hello";     // String

Try it Yourself »

Data types are divided into two groups:

  • Primitive data types - includes byte, short, int, long, float, double, boolean and char
  • Non-primitive data types - such as String, Arrays and Classes (you will learn more about these in a later chapter)

Primitive Data Types

A primitive data type specifies the size and type of variable values, and it has no additional methods.

There are eight primitive data types in Java:

Data Type Size Description
byte 1 byte Stores whole numbers from -128 to 127
short 2 bytes Stores whole numbers from -32,768 to 32,767
int 4 bytes Stores whole numbers from -2,147,483,648 to 2,147,483,647
long 8 bytes Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
float 4 bytes Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits
double 8 bytes Stores fractional numbers. Sufficient for storing 15 decimal digits
boolean 1 bit Stores true or false values
char 2 bytes Stores a single character/letter or ASCII values

Test Yourself With Exercises

Exercise:

Add the correct data type for the following variables:

 myNum = 9;
 myFloatNum = 8.99f;
 myLetter = 'A';
 myBool = false;
 myText = "Hello World";

Start the Exercise