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.[1]

Components Description Latest version Released
BCEL Byte Code Engineering Library - analyze, create, and manipulate Java class files 6.8.2 2024-02-21
BeanUtils Easy-to-use wrappers around the Java reflection and introspection APIs. 1.9.4 2019-06-12
BSF Bean Scripting Framework - interface to scripting languages, including JSR-223 3.1 2011-08-17
Chain Chain of Responsibility pattern implementation. 1.2 2008-06-01
CLI Command Line arguments parser. 1.6.0 2023-10-23
Codec General encoding/decoding algorithms (for example phonetic, base64, URL). 1.16.1 2024-02-04
Collections Extends or augments the Java Collections Framework. 4.5.0-M1 2024-03-31
Compress Defines an API for working with tar, zip and bzip2 files. 1.26.1 2024-03-05
Configuration Reading of configuration/preferences files in various formats. 2.10.1 2024-03-17
Crypto A cryptographic library optimized with AES-NI wrapping Openssl or JCE algorithm implementations 1.2.0 2023-01-14
CSV Component for reading and writing comma separated value files. 1.10.0 2023-01-28
Daemon A generic Daemon(unix) or Service (Windows) wrapper for Java code. 1.3.4 2023-05-10
DBCP Database connection pooling services. 2.12.0 2024-02-29
DbUtils JDBC helper library. 1.8.1 2023-09-09
Digester XML-to-Java-object mapping utility. 3.2 2011-12-13
Email Library for sending e-mail from Java. 1.5 2017-08-01
Exec API for dealing with external process execution and environment management in Java. 1.4.0 2024-01-01
FileUpload File upload capability for your servlets and web applications. 1.5 2023-02-13
Functor A functor is a function that can be manipulated as an object, or an object representing a single, generic function. 1.0 RC1 2011-10-20
Geometry General-purpose library for geometric processing. 1.0 2021-08-21
Imaging A pure-Java image library. 1.0-alpha4 2024-03-30
IO Collection of I/O utilities. 2.15.1 2023-11-24
JCI Java Compiler Interface 1.1 2013-10-14
JCS Java Caching System 3.2 2023-08-22
Jelly XML based scripting and processing engine. 1.0.1 2017-09-25
JEXL Expression language which extends the Expression Language of the JSTL. 4.0-snapshot.4 2019-05-24
JXPath Utilities for manipulating Java Beans using the XPath syntax. 1.3 2008-08-11
Lang Provides extra functionality for classes in java.lang. 3.14.0 2023-11-18
Logging Wrapper around a variety of logging API implementations. 1.3.0 2023-11-26
Math Lightweight, self-contained mathematics and statistics components. 4.0-beta1 2022-12-20
Net Collection of network utilities and protocol implementations. 3.10.0 2023-10-01
Numbers Number types (complex, quaternion, fraction) and utilities (arrays, combinatorics). 1.1 2022-11-01
OGNL An Object-Graph Navigation Language 4.0-incubating TBD
Pool Generic object pooling component. 2.12.0 2023-09-30
Proxy Library for creating dynamic proxies. 2.0-RC1 2014-04-07
RDF Common implementation of RDF 1.1 that could be implemented by systems on the JVM. 0.5.0 2017-12-08
RNG Commons RNG provides implementations of pseudo-random numbers generators. 1.5 2022-09-10
SCXML An implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine. 2.0-M1 2014-04-03
Statistics Utilities for statistical applications. 1.0 2022-12-05
Text A library focused on algorithms working on strings. 1.11.0 2023-10-24
Validator Framework to define validators and validation rules in an xml file. 1.8.0 2023-12-02
VFS Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system. 2.9.0 2021-06-16
Weaver Provides an easy way to enhance (weave) compiled bytecode. 2.0 2018-09-07

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.
Inject Implementation of JSR 330, a standards compliant dependency injection framework
Javaflow Continuation implementation to capture the state of the application.
JNet JNet allows using dynamically registered url stream handlers through the API.
Monitoring Monitoring aims to provide a simple but extensible monitoring solution for Java applications.
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.

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.
Discovery Tools for locating resources by mapping service/reference names to resource names.
EL Interpreter for the Expression Language defined by the JSP 2.0 specification.
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.
Launcher Cross platform Java application launcher.
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.
Modeler Mechanisms to create Model MBeans compatible with JMX specification.
Primitives Smaller, faster and easier to work with types supporting Java primitive types.
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


Goyal, Vikram (2003), Using the Jakarta Commons, Part I, retrieved August 13, 2006