| org.apache.commons.lang | Provides highly reusable static utility methods, chiefly concerned with adding value to java.lang and other standard core classes. |
| org.apache.commons.lang.builder | Assists in creating consistent equals(Object) , toString() , hashCode() , and compareTo(Object) methods. |
| org.apache.commons.lang.enums | Provides an implementation of the C style enum in the Java world. |
| org.apache.commons.lang.exception | Provides JDK 1.4 style Nested Exception functionality for those on prior Java versions. |
| org.apache.commons.lang.math | Extends java.math for business mathematical classes. |
| org.apache.commons.lang.mutable | Provides typed mutable wrappers to primitive values and Object. |
| org.apache.commons.lang.text | Provides classes for handling and manipulating text, partly as an extension to java.text . |
| org.apache.commons.lang.time | Provides classes and methods to work with dates and durations. |