Apache Commons

The Apache Commons is a project of the Apache Software Foundation, formerly under the Jakarta Project. The purpose of the Commons is to provide reusable, open source Java software. The Commons is composed of three parts: proper, sandbox, and dormant.

Commons Proper

The Commons Proper is dedicated to creating and maintaining reusable Java components. The Commons Proper is a place for collaboration and sharing, where developers from throughout the Apache community can work together on projects to be shared by Apache projects and Apache users. Commons developers will make an effort to ensure that their components have minimal dependencies on other software libraries, so that these components can be deployed easily. In addition, Commons components will keep their interfaces as stable as possible, so that Apache users, as well as other Apache projects, can implement these components without having to worry about changes in the future.

Components	Description	Latest Version	Released
BCEL	Byte Code Engineering Library - analyze, create, and manipulate Java class files	5.2	2007-06-14
BeanUtils	Easy-to-use wrappers around the Java reflection and introspection APIs.	1.9.2	2014-05-29
BSF	Bean Scripting Framework - interface to scripting languages, including JSR-223	3.1	2010-24-06
Chain	Chain of Responsibility pattern implemention.	1.2	2008-06-02
CLI	Command Line arguments parser.	1.2	2009-03-19
Codec	General encoding/decoding algorithms (for example phonetic, base64, URL).	1.9	2013-12-25
Collections	Extends or augments the Java Collections Framework.	4.0	2013-11-24
Compress	Defines an API for working with tar, zip and bzip2 files.	1.8.1	2014-05-14
Configuration	Reading of configuration/preferences files in various formats.	1.10	2013-10-27
CSV	Component for reading and writing comma separated value files.	1.0	2014-08-14
Daemon	Alternative invocation mechanism for unix-daemon-like java code.	1.0.15	2013-03-04
DBCP	Database connection pooling services.	2.0.1	2014-05-24
DbUtils	JDBC helper library.	1.6	2014-07-20
Digester	XML-to-Java-object mapping utility.	3.2	2011-12-13
Discovery	Tools for locating resources by mapping service/reference names to resource names.	0.5	2011-04-28
EL	Interpreter for the Expression Language defined by the JSP 2.0 specification.	1.0	2003-06-18
Email	Library for sending e-mail from Java.	1.3.3	2014-07-11
Exec	API for dealing with external process execution and environment management in Java.	1.2	2014-01-02
FileUpload	File upload capability for your servlets and web applications.	1.3.1	2014-02-07
Functor	A functor is a function that can be manipulated as an object, or an object representing a single, generic function.	N/A	N/A
Imaging	A pure-Java image library.	N/A	N/A
IO	Collection of I/O utilities.	2.4	2012-06-12
JCI	Java Compiler Interface	1.1	2013-10-14
JCS	Java Caching System	1.3	2007-06-05
Jelly	XML based scripting and processing engine.	1.0	2005-06-16
Jexl	Expression language which extends the Expression Language of the JSTL.	2.1.1	2011-12-24
JXPath	Utilities for manipulating Java Beans using the XPath syntax.	1.3	2008-08-14
Lang	Provides extra functionality for classes in java.lang.	3.3.2	2014-04-09
Launcher	Cross platform Java application launcher.	1.1	2004-08-22
Logging	Wrapper around a variety of logging API implementations.	1.2	2014-07-11
Math	Lightweight, self-contained mathematics and statistics components.	3.5	2015-04-17
Modeler	Mechanisms to create Model MBeans compatible with JMX specification.	2.0.1	2007-06-25
Net	Collection of network utilities and protocol implementations.	3.3	2013-06-12
OGNL	An Object-Graph Navigation Language	N/A	N/A
Pool	Generic object pooling component.	2.2	2014-02-24
Primitives	Smaller, faster and easier to work with types supporting Java primitive types.	1.0	2003-11-05
Proxy	Library for creating dynamic proxies.	1.0	2008-02-28
SCXML	An implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine.	0.9	2008-12-01
Validator	Framework to define validators and validation rules in an xml file.	1.4.0	2012-02-03
VFS	Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.	2.0	2011-08-24
Weaver	Provides an easy way to enhance (weave) compiled bytecode.	1.0	2014-03-16

Commons Sandbox

The Commons Sandbox provides a workspace where Commons contributors collaborate and experiment on projects not included in the Commons Proper. Commons members champion projects in the Sandbox for promotion to the Commons Proper, and groups of developers work to enhance Sandbox projects until they meet the standards for promotion.

Components	Description
BeanUtils2	Redesign of Commons BeanUtils.
ClassScan	Find Class interfaces, methods, fields, and annotations without loading.
CLI2	Redesign of Commons CLI.
Convert	Commons-Convert aims to provide a single library dedicated to the task of converting an object of one type to another.
Finder	Java library inspired by the UNIX find command.
Flatfile	Java library for working with flat data structures.
Graph	A general purpose Graph APIs and algorithms.
I18n	Adds the feature of localized message bundles that consist of one or many localized texts that belong together.
Id	Id is a component used to generate identifiers.
Javaflow	Continuation implementation to capture the state of the application.
JNet	JNet allows to use dynamically register url stream handlers through the java.net API.
Nabla	Nabla provides automatic differentiation classes that can generate derivative of any function implemented in the Java language.
OpenPGP	Interface to signing and verifying data using OpenPGP.
Performance	A small framework for microbenchmark clients, with implementations for Commons DBCP and Pool.
Pipeline	Provides a set of pipeline utilities designed around work queues that run in parallel to sequentially process data objects data objects.

Commons Dormant

The Commons Dormant is a collection of components that have been declared inactive due to little recent development activity. These components may be used, but must be built yourself. It is best to assume that these components will not be released in the near future.

Components	Description
Attributes	Runtime API to metadata attributes such as doclet tags.
Betwixt	Services for mapping JavaBeans to XML documents, and vice versa.
Cache	Cache provides object caching services.
Clazz	Clazz focuses on introspection and class manipulation.
Contract	This component makes all the nice features available to the java programming language that come along with contract based programming.
Convert	Commons-Convert aims to provide a single library dedicated to the task of converting an object of one type to another.
Events	Commons-Events provides additional classes for firing and handling events. It focusses on the Java Collections Framework, providing decorators to other collections that fire events.
Feedparser	A Java RSS/Atom parser designed to elegantly support all major versions of RSS and Atom, as well as easy ad hoc extension and RSS 1.0 modules capability.
JJar	Jakarta JAR Archive Repository
Latka	Commons-Latka is an HTTP functional testing suite for automated QA, acceptance and regression testing.
Mapper	Mapper is a thin abstraction layer around a project's chosen data mapping technology (a.k.a. DAO pattern).
Messenger	Messenger is an easy to use and lightweight framework for working with JMS in the web tier.
Resources	Resources provides a lightweight framework for defining and looking up internationalized message strings keyed by a java.util.Locale and a message key.
Scaffold	Scaffold is a toolkit for building web applications.
ThreadPool	ThreadPool is a simple component for asynchronously dispatching work to another thread in a pool for simple multi threaded programming.
Transaction	Implementations for multi level locks, transactional collections and transactional file access.
Workflow	Workflow provides a framework for building workflow management systems.
XMLIO	Simple and fast importer for XML configuration or import files.

See also

• Google Guava

External links

• Apache Commons
• Components page
• Sandbox page
• Dormant page
• Apache Commons popular APIs in GitHub