Summary of Numbers

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# Summary of Numbers

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.