Curriculum

Java Basic

Java Home

0/1

Java Introduction

0/1

Java Get Started

0/1

Java Syntax

0/1

Java Output / Print

0/2

Java Comments

0/1

Java Variables

0/5

Java Data Types

0/6

Java Type Casting

0/1

Java Operators

0/1

Java Strings

0/4

Java Math

0/1

Java Booleans

0/1

Java If ... Else

0/5

Java Switch

0/1

Java While Loop

0/3

Java For Loop

0/4

Java Break / Continue

0/1

Java Arrays

0/4

Java Methods

0/6

Java Classes

0/26

Java file Handling

0/4

Java How To

0/16

Java Reference

0/53

Java String Methods

0/39

Java Math Methods

0/48

Java Output Methods

0/4

Java Arrays Methods

0/6

Java ArrayList Methods

0/26

Java LinkedList Methods

0/27

Java HashMap Methods

0/23

Java Errors and Exception

0/1

Text lesson

Data Types

Java Data Types

As previously mentioned, every variable in Java must have a defined 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

Data types are categorized into two groups:

Primitive data types – comprise byte, short, int, long, float, double, boolean, and char.
Non-primitive data types – encompass String, Arrays, and Classes (further details on these will be covered in subsequent chapters).

Primitive Data Types

Primitive data types in Java define the size and type of variable values and do not possess additional methods.

Java encompasses eight primitive data types:

Data Type	Size	Description
`Byte`	1 byte	Stores integers ranging from -128 to 127
`Short`	2 bytes	Stores integers ranging from – 32,768 to 32,767
`Int`	4 bytes	Stores integers ranging from – 2,147,483,648 to 2,147,483,647
`Long`	8 bytes	Stores integers ranging from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
`Float`	4 bytes	Stores fractional numbers with accuracy up to 6 to 7 decimal digits
`Double`	8 bytes	Stores fractional numbers with precision up to 15 decimal digits
`Boolean`	1 bit	Store values representing true or false
`char`	2 bytes	Stores a single character or ASCII values