What is Data Types in Java?
The term data type refers to the type of data that can be stored in a
variable.
Sometimes, Java is called a “strongly typed language” because when you declare
a variable, you must specify the variable’s type.
Java has a rich set of data types. Data types in Java can be divided into
two parts :
1. Primitive Data Types :- which include
integer, character, boolean, and float
2. Non-primitive Data Types :- which include
classes, arrays and interfaces.
Primitive Data Types
Primitive Data
Types are predefined and available within the Java language. Primitive values
do not share state with other primitive values.
There are 8
primitive types: byte, short, int, long, char, float, double, and Boolean.
Integer data types
·
byte (1 byte)
·
short (2 bytes)
·
int (4 bytes)
·
long (8 bytes)
1. 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 int.
Example: byte a = 100 , byte b = -50
2. 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)
Short data type can also be used to save memory as byte data type. A short is 2
times smaller than an int
Default value is 0.
Example: short s = 10000, short r = -20000
3. 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)
Int 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 ab = 10000, int bc = -20000
4. 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 = 1000L, int b = -2000L
·
float (4 bytes)
·
double (8 bytes)
5. 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 fa1 = a234.5f
6. double:
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 dz1 = 1233.4
Textual Data Type
char (2 bytes)
7. 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 letterA ='A'
Logical
boolean (1 byte)
(true/false)
8. 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
|
Java Data
Types |
||
|
Data Type |
Default Value |
Default size |
|
byte |
0 |
1 byte |
|
short |
0 |
2 bytes |
|
int |
0 |
4 bytes |
|
long |
0L |
8 bytes |
|
float |
0.0f |
4 bytes |
|
double |
0.0d |
8 bytes |
|
boolean |
false |
1 bit |
|
char |
‘\u0000’ |
2 bytes |
Points to
Remember:
- All numeric data types
are signed(+/-).
- The size of data types
remain the same on all platforms (standardized)
· char data type in Java is 2
bytes because it uses UNICODE character set.
