Chapter 10. Lang

Almost every development project winds up with a lot of strange little utility functions, often buried in a class named something like "Utils." Common examples include a utility function for escaping a bit of HTML or SQL, or a quick class to make it easier to return a Date object formatted to a particular locale. The Lang package is essentially a fifty-odd set of these utilities.

The difficult thing about the Lang package is not any particular complexity, but rather simply remembering what functionality is present. In this chapter, we provide a general overview of the Lang package. It may seem easy to write your own utility methods, but those thirty minute one-offs can start to add upand other developers familiar with the Lang package will immediately know where to find and how to use those utility routines.

The Lang package is split up into six main packages:

org.apache.commons.lang	A wide variety of miscellaneous routines.
org.apache.commons.lang.builder	Assists in creating consistent equals(Object), toString(), hashCode(), and compareTo(Object) methods.
org.apache.commons.lang.enum	Support for type-safe Java enums.
org.apache.commons.lang.exception	Provides JDK 1.4 style nested exceptions on earlier versions of the JDK.
org.apache.commons.lang.math	Fractions, ranges, random numbers, and some additional math-related utilities.
org.apache.commons.lang.time	Formatting, stopwatch, and a variety of other time-related utilities.