Data types

Data is categorized into types. A data type identifies not only the form of the data but also what kind of operations can be performed upon it. For example, arithmetic operations can be performed on numerical data, but not on text data.

A data type can also determine how much computer storage space an item requires. For example, a decimal value like 3.14 would normally be stored in a 32-bit (four bytes) slot, while a web address such as https://google.com might occupy 160 bits.

Here is a categorization of the main data types that we will be working with in this book. The corresponding Java types are shown in parentheses: