Data types in Java . dEexams.com

Primitive data types : JAVA

There are majorly two types of languages. First one is Statically typed language where each variable and expression type is already known at compile time.Once a variable is declared to be of a certain data type, it cannot hold values of other data types.Example: C,C++, Java. Other, Dynamically typed languages: These languages can receive different data types over the time. Ruby, Python

Java has two categories of data:

Primitive data (e.g., number, character)
Object data (programmer created types)

Primitive data are only single values; they have no special capabilities.
The eight primitive data types in Java are:

boolean, the type whose values are either true or false
char, the character type whose values are 16-bit Unicode characters
the arithmetic types:
- the integral types:
  - byte
  - short
  - int
  - long
- the floating-point types:
  - float
  - double

Values of class type are references. Strings are references to an instance of class String.

Primitive data types in Java
Type	Default	Size	Example Literals
boolean	false	1 bit	`true`, `false`
byte	0	8 bits	(none)
char	`u0000`	16 bits	`'a'`, `'u0041'`, `'101'`, `'`, `\\''`, `' '`, `'ß'`
short	0	16 bits	(none)
int	0	32 bits	`-2`, `-1`, `0`, `1`, `2`
long	0	64 bits	`-2L`, `-1L`, `0L`, `1L`, `2L`
float	0.0	32 bits	`1.23e100f`, `-1.23e-100f`, `.3f`, `3.14F`
double	0.0	64 bits	`1.23456e300d`, `-1.23456e-300d`, `1e1d`

Boolean

Values of type boolean are not converted implicitly or explicitly (with casts) to any other type. But the programmer can easily write conversion code:

final int i = b?1:0;
final double d = b?1.0:0.0;
final boolean b = i>0?true:false;

Character

The 16-bit Unicode character set underlies both the Java source program and char data type. So, not only are Java programs written in Unicode characters, but Java programs can manipulate Unicode data.

Numeric

Range of numeric data types in Java
Type	Size	Range
byte	8 bits	-128 .. 127
short	16 bits	-32,768 .. 32,767
int	32 bits	-2,147,483,648 .. 2,147,483,647
long	64 bits	-9,223,372,036,854,775,808 .. 9,223,372,036,854,775,807
float	32 bits	3.40282347 x 10³⁸, 1.40239846 x 10^-45
double	64 bits	1.7976931348623157 x 10³⁰⁸, 4.9406564584124654 x 10^-324

Uk01 on Jan 20, 2015 at 12:01 am

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