Documentation

The Java™ Tutorials

Summary of Numbers

The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases.

You use one of the wrapper classes – `Byte`

, `Double`

, `Float`

, `Integer`

, `Long`

, or `Short`

– to wrap a number of primitive type in an object. The Java compiler automatically wraps (boxes) primitives for you when necessary and unboxes them, again when necessary.

The `Number`

classes include constants and useful class methods. The `MIN_VALUE`

and `MAX_VALUE`

constants contain the smallest and largest values that can be contained by an object of that type. The `byteValue`

, `shortValue`

, and similar methods convert one numeric type to another. The `valueOf`

method converts a string to a number, and the `toString`

method converts a number to a string.

To format a string containing numbers for output, you can use the `printf()`

or `format()`

methods in the `PrintStream`

class. Alternatively, you can use the `NumberFormat`

class to customize numerical formats using patterns.

The `Math`

class contains a variety of class methods for performing mathematical functions, including exponential, logarithmic, and trigonometric methods. `Math`

also includes basic arithmetic functions, such as absolute value and rounding, and a method, `random()`

, for generating random numbers.