Data types in Java

Java Programming Java8Object Oriented ProgrammingJava Technologies

There are two data types available in Java −

  • Primitive Data Types
  • Reference/Object Data Types

Primitive Data Types

There are eight primitive data types supported by Java. Primitive data types are predefined by the language and named by a keyword. Let us now look into the eight primitive data types in detail.

byte

  • Byte data type is an 8-bit signed two's complement integer

  • Minimum value is -128 (-2^7)

  • Maximum value is 127 (inclusive)(2^7 -1)

  • Default value is 0

  • Byte data type is used to save space in large arrays, mainly in place of integers, since a byte is four times smaller than an integer.

  • Example − byte a = 100, byte b = -50

short

  • 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)

  • Integer is generally used as the default data type for integral values unless there is a concern 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

  • 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

  • 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 generally used as the default data type for decimal values, generally the default choice

  • Double data type should never be used for precise 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

  • Default value is false

  • Example − boolean one = true

char

  • 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 letter A = '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 type of array variables come under reference data type.

  • The default value of any reference variable is null.

  • A reference variable can be used to refer any object of the declared type or any compatible type.

  • Example − Animal animal = new Animal("giraffe");

raja
Published on 06-Feb-2018 01:13:24
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