Objects and Primitive Data

A primitive data type uses a small amount of memory to represent data using bit patterns. For example, primitive type int represents integers using 32 bits. There are only eight primitive data types in Java: byte, short, int, long, float, double, char, and boolean. It is not possible for a Java program to define any other primitive data types.

An object is a large chunk of memory that can potentially contain a great deal of data along with methods (little programs) to process data. There are hundreds of object classes that come standard with Java, and a programmer can easily create additional classes.

Objects are so useful that we need to start using them now, even though they will not be fully discussed until chapter 25.