Java Basic Datatypes

Variables are nil but kept memory places to amass values. This denotes that when you make a variable you set aside some space in the memory.

Stand on the data kind of a variable, the operating system assigns memory and chooses what can be amassed in the preserved memory. Consequently, when allotting the diverse data types to variables, you container store integers, decimals, or characters in these variables.

There are two data types available in Java −

• Primitive Data Types
• Reference/Object Data Types

Primitive Data Types

There are eight ancient datatypes reinforced by Java. Ancient data types are predefined by the language and surnamed by a keyword. Let us now appear into the eight ancient data types in aspect.

byte

• The byte data type is an 8-bit signed two's complement integer
• The minimum value is -128 (-2^7)
• The maximum value is 127 (inclusive)(2^7 -1)
• The default value is 0
• The byte data type is employed to save space in great arrays, mostly in place of integers, while a byte is four times smaller than an integer.
• Example: byte a = 100, byte b = -50

short

• The short data type is a 16-bit signed two's complement integer
• Minimum value is -32,768 (-2^15)
• Maximum value is 32,767 (inclusive) (2^15 -1)
• The short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer
• The default value is 0.
• Example: short s = 10000, short r = -20000

int

• Int data type is a 32-bit signed two's complement integer.
• Minimum value is - 2,147,483,648 (-2^31)
• Maximum value is 2,147,483,647(inclusive) (2^31 -1)
• An integer is normally employed as the default data type for vital values except there is an anxiety about memory.
• The default value is 0
• Example: int a = 100000, int b = -200000

long

• Long data type is a 64-bit signed two's complement integer
• Minimum value is -9,223,372,036,854,775,808(-2^63)
• Maximum value is 9,223,372,036,854,775,807 (inclusive)(2^63 -1)
• This type is used when a wider range than int is needed
• Default value is 0L
• Example: long a = 100000L, long b = -200000L

float

• The float data type is a single-precision 32-bit IEEE 754 floating point
• Float is mainly used to save memory in large arrays of floating-point numbers
• Default value is 0.0f
• The float data type is never used for precise values such as currency
• Example: float f1 = 234.5f

double

• the double data type is a double-precision 64-bit IEEE 754 floating point
• This data type is usually employed as the default data type for decimal values, normally the default alternative
• The double data type should never be utilized for accurate values such as currency
• Default value is 0.0d
• Example: double d1 = 123.4

boolean

• Boolean data type represents one bit of information
• There are only two possible values: true and false
• This data type is used for simple flags that track true/false conditions
• The default value is false
• Example: boolean one = true

char

• the char data type is a single 16-bit Unicode character
• Minimum value is '\u0000' (or 0)
• Maximum value is '\uffff' (or 65,535 inclusive)
• Char data type is used to store any character
• Example: char letterA = 'A'

Reference Datatypes

• Reference variables are created using defined constructors of the classes. They are used to access objects. These variables are declared to be of a specific type that cannot be changed. For example, Employee, Puppy, etc.
• Class objects and various types of array variables come under reference datatype.
• The default value of any reference variable is null.
• A reference variable can be used to refer to any object of the declared type or any compatible type.
• Example: Animal animal = new Animal("giraffe");

Java Literals

A literal is a source code representation of a fixed value. They are represented directly in the code without any computation.

Literals can be assigned to any primitive type variable. For example −

byte a = 68;
char a = 'A';

byte, int, long, and short can be expressed in decimal(base 10), hexadecimal(base 16), or octal(base 8) number systems as well.

Prefix 0 is used to indicate octal, and prefix 0x indicates hexadecimal when using these number systems for literals. For example:

int decimal = 100;
int octal = 0144;
int hexa =  0x64;

String literals in Java are specified like they are in most other languages by enclosing a sequence of characters between a pair of double-quotes. Examples of string literals are:

"Hello World"
"two\nlines"
"\"This is in quotes\""

Example

"Hello World"
"two\nlines"
"\"This is in quotes\""

String and char types of literals can contain any Unicode characters. For example:

char a = '\u0001';
String a = "\u0001";

Java language supports few special escape sequences for String and char literals as well. They are: