Data Types in Java
All variables in the java must have a data type. A variable's type determines the values that the variable store and the operations that can be performed on it.
The Java programming language is strictly-typed, which means that all variables must first be declared before they can be used. Data types can be categorized as two –
- Primitive data types
- Non - primitive data types
Primitive Data Types in Java
A primitive type is predefined by the language and is named by a reserved keyword. There are eight primitive data types supported by Java:
There are 8 types of primitive data types:
- boolean data type
- byte data type
- char data type
- short data type
- int data type
- long data type
- float data type
- double data type
Byte Data Type
The byte data type is an 8 bit signed integer. It ranges from -128 to 127. It can be declared as
byte b=5;
Short Data Type
The short data type is a 16 bit signed integer. It ranges from -32,768 to 32,767. It can be declared as
short s = 2;
Int Data Type
The int data type is used to store the integer values, not the fraction values. It is a 32 bit signed integer data type. It ranges from -2,147,483,648 to 2,147,483,647 that is more enough to store large number in the program. It can be declared as
int num = 50;
Long Data Type
The long data type is a 64 bi signed integer. It ranges from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807. It can be declared as
long ln = 759;
Float Data Type
The float data type is a 64 bit IEEE 754 floating point. It ranges from 1.40129846432481707e-45 to 3.40282346632528860e+38 (positive or negative). Use a float (instead of double) to save memory in large arrays. It can be declared as
float f=123.45;
float f1 = -1000.44;
Double Data Type
This data type is a double precision 64 bit IEEE 754 floating point. It ranges from 4.94065645841246544e-324d to 1.7976933486231570e+308d (positive or negative). This data type is normally a default choice for floating values. It can be declared as
double d = 1254.77
Char Data Type
The char data type is a single 16 bit signed Unicode character. It ranges from 0 to 65,535. It can be declared as
char ch = ‘k’;
Boolean Data Type
The Boolean data type represents only two values: true and false and occupy 1 ut in the memory. It can be declared as
boolean result = true;
Here is the list of primitive data types with their details
| Type | Contains | Default | Size | Range |
| boolean | true or false | false | 1 bit | True/False, Yes/No, 0/1 |
| char | Unicode character | \u0000 | 16 bit | 0 to 65,536 |
| byte | Signed integer | 0 | 8 bits | -128 to 127 |
| short | Signed integer | 0 | 16 bits | -32786 to 32767 |
| int | Signed integer | 0 | 32 bits | -2147483648 to 2147483647 |
| long | Signed integer | 0 | 64 bits | -9223372036854775808 to 9223372036854775807 |
| float | IEEE 754 floating point | 0.0 | 32 bits | 1.4e – 045 to 3.4e + 038 |
| double | IEEE 754 floating point | 0.0 | 64 bits | 4.9e - 324 to 1.8e + 308 |
Data type char takes 2 bytes to store a character because java uses the Unicode system rather than the ASCII code system \u0000 is the lowest range of Unicode system.
Java provides special support for character strings using java.lang.String class. Enclosing character string within double quotes (“”) will automatically create String objects.
It can be declared as –
String str = “My Name Is JAVA”.
Non-Primitive Data Types in Java
The non-primitive data types include Classes, Interfaces, and Arrays.