Summary of Numbers
You use one of the wrapper classes –
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.
Number classes include constants and useful class methods. The
MAX_VALUE constants contain the smallest and largest values that can be contained by an object of that type. The
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
format() methods in the
PrintStream class. Alternatively, you can use the
NumberFormat class to customize numerical formats using patterns.
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.