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Java Data Types.md

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Data Types

Java is a statically-typed programming language which means that all variables must be declared before they are used.

The variable declaration specifies the data type of the variable.

The data type of variable determines the size and type of values that can be stored in the variable.

Primitive Data Types

Primitive data types are predefined by the language and are named by a keyword. They are divided into two categories: Numeric and Non-Numeric

Integer Types

Type Size Range
byte 1 byte -128 to 127
short 2 bytes -32,768 to 32,767
int 4 bytes -2,147,483,648 to 2,147,483,647
long 8 bytes -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

Floating Point Types

Type Size Range
float 4 bytes 1.4e-45 to 3.4028235e+38
double 8 bytes 4.9e-324 to 1.7976931348623157e+308

Character Type

Type Size Range
char 2 bytes 0 to 65,535

Boolean Type

Type Size Range
boolean 1 bit true or false

Non-Primitive Data Types

Non-primitive data types are also called reference types. They are created by the programmer and are used to call methods to perform certain operations on the data.

String

A string is a sequence of characters. It is a non-primitive data type. It is used to store text.

String name="John";

Class

A class is a user-defined data type. It is a non-primitive data type. It is used to store data and methods that act on the data.

class Person {
    String name;
    int age;
}