Java Data-types

Data Types in Java

Last Updated: 10 July, 2023

In programming languages, a data type is a classification of data that tells the compiler or interpreter of that programming language how the programmer intends to use the data.

Java is a statically typed programming language, which means that variables must be declared with a specific data type before they can be used.

Java supports various types of data like String, Integer, Character, Decimals, Boolean, etc. These different data types allocate some memory and accept values according to their nature.

When choosing a data type for a variable, it is important to consider the size and range of values that the variable will need to store. For example, if the variable will only store whole numbers from 0 to 99, then the byte data type would be a good choice.

There are two types of data types supported by Java:

Primitive data types

Non-primitive data types

Primitive Data Type

Primitive data types are predefined by the Java language and named by a keyword. Primitive values do not share a state with other primitive values.

There are a total of 8 primitive data types in Java: byte, char, short, int, long, float, double, and boolean. Every primitive data type has a default value and occupies a different amount of memory.

See below all 8 primitive data types' names and details about each in the given table.

Table of Java Primitive Data Types

Data Type	Range of Values	Default Value	Allocates Memory
`boolean`	true / false	false	1 bit

`byte`	-128 to 127	0	8 bits

`char`	Character representation of ASCII values 0 to 255	'\u0000'	2 byte

`short`	-32768 to 32767	0	16 bits

`int`	- 2,147,483,648 to 2,147,483,647	0	32 bits

`long`	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	0L	64 bits

`float`	3.4e−038 to 3.4e+038	0.0F	32 bits

`double`	1.7e−308 to 1.7e+308	0.0d	64 bits

Data Type

Range of Values

Default Value

Allocates Memory

boolean

true / false

false

1 bit

byte

-128 to 127

8 bits

char

Character representation of ASCII values 0 to 255

'\u0000'

2 byte

short

-32768 to 32767

16 bits

int

- 2,147,483,648 to 2,147,483,647

32 bits

long

-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

64 bits

float

3.4e−038 to 3.4e+038

0.0F

32 bits

double

1.7e−308 to 1.7e+308

0.0d

64 bits

  public class PrimitiveDateTypesExample {
    // Declaring all 8 Primitive Data Types
    byte byteData;
    short shortData;
    int intData;
    long longData;
    float floatData;
    double doubleData;
    char charData;
    boolean booleanData;
    
    public static void main(String[] args) {
      PrimitiveDateTypesExample obj = new PrimitiveDateTypesExample();
      
      // Printing the default value of each primitive data types
      System.out.println("byteData : " + obj.byteData);
      System.out.println("shortData : " + obj.shortData);
      System.out.println("intData : " + obj.intData);
      System.out.println("longData : " + obj.longData);
      System.out.println("floatData : " + obj.floatData);
      System.out.println("doubleData : " + obj.doubleData);
      System.out.println("charData : " + obj.charData);
      System.out.println("booleanData : " + obj.booleanData);
    }
  }

byteData : 0
shortData : 0
intData : 0
longData : 0
floatData : 0.0
doubleData : 0.0
charData :
booleanData : false

Non-Primitive Data Type

A non-Primitive data type is also known as a Reference data type in Java. The Reference Data Types don't store variable values directly in memory; they only contain the memory address of those variable values. For example, user-defined classes, String, ArrayList, etc.

Data Types in Java

Primitive Data Type

Table of Java Primitive Data Types

Non-Primitive Data Type

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