Data Types in Java with Examples
In Java, data types specify the type of data that a variable can hold.
Here is an example that shows how data types are used in Java:
String stringValue = "Hello" byte byteNumber = 100; short shortNumber = 1344; int intNumber = 1034345; long longNumber = 1092929292; float floatNumber = 10; double doubleNumber = 20.34; boolean boolValue = true; char charValue = 'n';
In the above example, String, byte, short, int, long, float, double, boolean, char are data types.
There are two types of data types in Java:
- Primitive data types
- Non-primitive data types
Primitive Data Types
Primitive types are the most basic data types in Java. They are built-in and available in the Java language. There are eight primitive data types in Java:
Data Type | Size | Description |
byte | 8 bit | Can store value from -128 to 127 |
short | 16-bit | Can store value from -32,768 to 32,767 |
int | 32-bit | Can store value from -2,147,483,648 to 2,147,483,647 |
long | 64-bit | Can store from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
float | 32-bit single-precision | Store value from 3.402,823,5 E+38 to 1.4 E-45 |
double | 64-bit double-precision | Can store value from 1.797,693,134,862,315,7 E+308 to 4.9 E-324 |
boolean | 1-bit | Can store true or false |
char | 16-bit | Can store unicode character value from '\u0000' (or 0) to '\uffff' |
Example:
public class PrimitiveDatatypesExample { public static void main(String[] args) { byte byteNumber = 100; short shortNumber = 1344; int intNumber = 1034345; long longNumber = 1092929292; float floatNumber = 10; double doubleNumber = 20.34; boolean boolValue = true; char charValue = 'a'; System.out.println(byteNumber); System.out.println(shortNumber); System.out.println(intNumber); System.out.println(longNumber); System.out.println(floatNumber); System.out.println(doubleNumber); System.out.println(boolValue); System.out.println(charValue); } }
The output of the above code is as follows:
100 1344 1034345 1092929292 10.0 20.34 true a
Non-primitive Data Types
Non-primitive data types are also called reference types. A reference data type can be used to refer to String, Classes, and Arrays type. A reference type does not store values but store reference to that value in memory.
String text = new String(); Student student = new Student(); Dog dog = new Dog(); User user = new User();
The default value of a reference variable is null.
Java is Strongly Typed and Type-safe
Java is strongly typed language which means a variable declared with an integer data type cannot be assigned a floating point number (a number with a decimal point).
Java language is designed to be type-safe which means all the data types declared in the program are checked during compilation so as to ensure that the operations are performed on right kind of data.