Java Data Types

As explained in the previous chapter, a variable in Java must be a specified 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

Data types are divided into two groups:

• 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

A primitive data type specifies the size and type of variable values, and it has no additional methods.

There are eight primitive data types in Java:

Data TypeSizeDescriptionbyte1 byteStores whole numbers from -128 to 127short2 bytesStores whole numbers from -32,768 to 32,767int4 bytesStores whole numbers from -2,147,483,648 to 2,147,483,647long8 bytesStores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807float4 bytesStores fractional numbers. Sufficient for storing 6 to 7 decimal digitsdouble8 bytesStores fractional numbers. Sufficient for storing 15 decimal digitsboolean1 bitStores true or false valueschar2 bytesStores a single character/letter or ASCII values