Data Types
Java Data Types
As previously mentioned, a variable in Java needs to be of a specific data type:
Example
int myNum = 5; // Integer (whole number)
float myFloatNum = 5.99f; // Floating point number
char myLetter = 'D'; // Character
boolean myBool = true; // Boolean
String myText = "Hello"; // String
There are two groups of data types:
- Primitive data types – includes byte, short, int, long, float, double, boolean and char
- Non-primitive data types – such as String, Arrays and Classes (you will learn more about these in a later chapter)
Primitive Data Types
Primitive data types have no further methods and only define the size and kind of variable values.
In Java, there are eight basic data types:
| Data Type | Size | Description |
|---|---|---|
byte |
1 byte | Stores whole numbers from -128 to 127 |
short |
2 bytes | Stores whole numbers from -32,768 to 32,767 |
int |
4 bytes | Stores whole numbers from -2,147,483,648 to 2,147,483,647 |
long |
8 bytes | Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
float |
4 bytes | Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits |
double |
8 bytes | Stores fractional numbers. Sufficient for storing 15 decimal digits |
boolean |
1 bit | Stores true or false values |
char |
2 bytes | Stores a single character/letter or ASCII values |
