DATA TYPES IN JAVA

    The Primitive Types:Java defines eight primitive types of data:

byte,short,int,long,char,float,double and boolean.

The primitive types are also commonly referred to as simple types.

    Integers:

o   Includes byte, short, int and long.

o   All of these are signed, positive and negative values.

Name	Width	Range
Long	64	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
Int	32	-2,147,483,648 to 2,147,483,647
Short	16	-32,768 to 32,767
Byte	8	-128 to 127

o   byte:

§  Smallest integer type.

§  Useful when working with a stream of data from a network or file.

§  Useful when working with row binary data that may not be directly compatible with Java’s other built-in types.

§  Declared by using byte keyword:

byte a,b;

o   short:

§  Signed 16 bit type.

§  Probably the least used Java type.

§  Declared by using shortkeyword:

short a,b;

o   int:

§  Signed 32 bit type.

§  Most commonly used integer type.

§  Generally used to control loops and to index arrays.

§  Declared by using int keyword:

int a,b;

o   long:

§  Signed 64 bit type.

§  Useful in occasions where an int type is not large enough to hold the desired value.

§  Declared by using long keyword:

long a,b;

    Floating-Point Types:

o   Includes float and double.

o   Also known as real numbers.

o   Used when evaluating expressions that requires fraction precision.

Name	Width	Range
Double	64	4.9e-324 to 1.8e+308
Float	32	1.4e-045 to 3.4e+038

o   float:

§  Specifies a single-precision value.

§  Useful when needed a fractional components, but don’t require a large degree of precision.

§  Declared by using float keyword:

float a,b;

o   double:

§  Specifies a double-precision value.

§  Useful when needed to maintain accuracy over many iterative calculations, or are manipulating large-valued numbers.

§  Declared by using double keyword:

double a,b;

    Character Types:

o   Includes char.

o   In Java char is 16-bit type. The range of char is 0 to 65,536.

o   char data type can be used to perform arithmetic operations.

o   Declared by using char keyword:

char a,b; 

    Boolean Types:

o   Includes boolean.

o   It can have one of two possible values, true or false.

o   Used when conditional expressions that govern the control statements such as if or for are evaluated.

o   Declared by using boolean keyword:

boolean b;