Java Data Types Explained – Primitive and Non-Primitive

 

Data Types in Java:

Introduction

In Java programming, data types play a very important role. A data type defines the type of value a variable can store. For example, some variables store numbers, some store characters, and some store true/false values.

Types of Data Types in Java

In Java, data types are mainly divided into two categories:

1. Primitive Data Types

2. Non-Primitive (Reference) Data Types
   

1. Primitive Data Types in Java

Primitive data types are the basic built-in data types provided by Java and used to store simple values like numbers, characters, and true/false values. They are not objects and store actual values directly in memory, which makes them fast and memory efficient.

Java has 8 primitive data types.

Data Type	Description	Example
byte	Stores small integers	byte a = 10;
short	Stores slightly larger integers	short b = 200;
int	Stores whole numbers	int marks = 85;
long	Stores very large numbers	long population = 9000000;
float	Stores decimal numbers	float price = 10.5f;
double	Stores large decimal values	double pi = 3.14159;
char	Stores a single character	char grade = 'A';
boolean	Stores true or false values	boolean pass = true;

1. byte

• Used to store small integer numbers.

• Memory size: 1 byte (8 bits)

• Range: -128 to 127

Example:

byte age = 25;

---

2. short

• Used for storing slightly larger integers than byte.

• Memory size: 2 bytes (16 bits)

• Range: -32,768 to 32,767

Example:

short temperature = 120;

---

3. int

• Most commonly used integer data type.

• Memory size: 4 bytes (32 bits)

• Range: -2,147,483,648 to 2,147,483,647

Example:

int marks = 95;

---

4. long

• Used to store very large integer values.

• Memory size: 8 bytes (64 bits)

• Range: -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

Example:

long population = 7800000000L;

---

5. float

• Used to store decimal numbers (single precision).

• Memory size: 4 bytes

• Precision: about 6–7 decimal digits

Example:

float price = 45.75f;

---

6. double

• Used for large decimal numbers (double precision).

• Memory size: 8 bytes

• Precision: about 15 decimal digits

Example:

double distance = 12345.6789;

---

7. char

• Used to store a single character.

• Memory size: 2 bytes (16 bits)

• Range: 0 to 65,535 (Unicode characters)

Example:

char grade = 'A';

---

8. boolean

• Used to store true or false values.

• Memory size: 1 bit (logical value)

Example:

boolean isPassed = true;

---

Primitive Data Types Table

Data Type	Size	Range / Capacity	Example
byte	1 byte	-128 to 127	byte b = 10;
short	2 bytes	-32,768 to 32,767	short s = 200;
int	4 bytes	-2,147,483,648 to 2,147,483,647	int i = 500;
long	8 bytes	Very large integers	long l = 10000L;
float	4 bytes	6–7 decimal digits	float f = 5.5f;
double	8 bytes	15 decimal digits	double d = 10.25;
char	2 bytes	Unicode characters	char c = 'A';
boolean	1 bit	true / false	boolean flag = true;

Non-Primitive Data Types:

Non-primitive data types are also known as Reference Data Types because they store the reference (address) of the object in memory instead of the actual value. Non-Primitive Data Types are data types that are created using classes and can store multiple values or complex data.

Unlike primitive data types, they:

• Can store multiple values

• Have methods and properties

• Are created by the programmer or provided by Java

Types of Non-Primitive Data Types in Java

The most common non-primitive data types are:

1. String

2. Array

3. Class

4. Object

5. Interface

Features of Non-Primitive Data Types

Non-primitive data types have the following features:

• They are created using classes

• They can store multiple values

• They support methods and functions

• They store references instead of actual data

• They are used to build complex programs

Difference Between Primitive and Non-Primitive Data Types

Feature	Primitive Data Type	Non-Primitive Data Type
Storage	Stores actual value	Stores reference
Size	Fixed	Not fixed
Examples	int, float, char	String, Array, Class
Complexity	Simple	Complex

Source: ChatGPT, Morning Star