Cayenne is a powerful, full-featured, opensource framework created for developers working with relational databases. it seamlessly maps any relational database to Java objects, reducing development time and adding considerable functionality to any application which requires a database. Developers using Cayenne will be able to concentrate on the core business requirements and the data model instead of the SQL details. The application can then be easily moved to any JDBC-capable database. In addition to management of persistent Java objects mapped to relational databases, Cayenne provides a plethora of features including single method call queries and updates (including atomic updates of all modified objects), seamless integration of multiple databases into a single virtual data source, three tier persistence with caching on the remote client, paging of results, record locking, and many more features. JPA compliance is in progress.

HttpCore is a set of low level HTTP transport components that can be used to build custom client and server side HTTP services with a minimal footprint. HttpCore supports two I/O models: blocking I/O model based on the classic Java I/O and non-blocking, event driven I/O model based on Java NIO. The blocking I/O model may be more appropriate for data intensive, low latency scenarios, whereas the non-blocking model may be more appropriate for high latency scenarios where raw data throughput is less important than the ability to handle thousands of simultaneous HTTP connections in a resource efficient manner.

Apache Jakarta JMeter may be used to test performance both on static and dynamic resources (files, Servlets, Perl scripts, Java Objects, Data Bases and Queries, FTP Servers and more). It can be used to simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types. You can use it to make a graphical analysis of performance or to test your server/script/object behavior under heavy concurrent load.

Commons-Email aims to provide a API for sending email. It is built on top of the Java Mail API, which it aims to simplify.

The goal of Tobago is to provide the community with a well designed set of user interface components based on JSF.

Commons Object Pooling Library

The mission of the Apache Portable Runtime (APR) project is to create and maintain software libraries that provide a predictable and consistent interface to underlying platform-specific implementations. The primary goal is to provide an API to which software developers may code and be assured of predictable if not identical behaviour regardless of the platform on which their software is built, relieving them of the need to code special-case conditions to work around or take advantage of platform-specific deficiencies or features.

The mission of the Apache Portable Runtime (APR) project is to create and maintain software libraries that provide a predictable and consistent interface to underlying platform-specific implementations. The primary goal is to provide an API to which software developers may code and be assured of predictable if not identical behaviour regardless of the platform on which their software is built, relieving them of the need to code special-case conditions to work around or take advantage of platform-specific deficiencies or features.

The mission of the Apache Portable Runtime (APR) project is to create and maintain software libraries that provide a predictable and consistent interface to underlying platform-specific implementations. The primary goal is to provide an API to which software developers may code and be assured of predictable if not identical behaviour regardless of the platform on which their software is built, relieving them of the need to code special-case conditions to work around or take advantage of platform-specific deficiencies or features.

The mission of the Apache Portable Runtime (APR) project is to create and maintain software libraries that provide a predictable and consistent interface to underlying platform-specific implementations. The primary goal is to provide an API to which software developers may code and be assured of predictable if not identical behaviour regardless of the platform on which their software is built, relieving them of the need to code special-case conditions to work around or take advantage of platform-specific deficiencies or features.

Apache MINA is a network application framework which helps users develop high performance and high scalability network applications easily. It provides an abstract, event-driven, asynchronous API over various transports such as TCP/IP and UDP/IP via Java NIO.

VelocityTools is a collection of Velocity subprojects with a common goal of creating tools and infrastructure for building both web and non-web applications using the Velocity template engine.

Apache Jakarta JMeter may be used to test performance both on static and dynamic resources (files, Servlets, Perl scripts, Java Objects, Data Bases and Queries, FTP Servers and more). It can be used to simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types. You can use it to make a graphical analysis of performance or to test your server/script/object behavior under heavy concurrent load.

Commons Compress: working with zip, ar, jar, bz2, cpio and gz files.

mod_perl is a unique piece of software that integrates the power of Perl with the flexibility and stability of the Apache Web server. With mod_perl, you can harness the power of the full Apache API with Perl and develop Web applications quickly, without sacrificing performance.

Apache Derby is an open source relational database implemented entirely in Java. It has a small footprint that makes it easy to embed in any Java-based application, but it also supports the more familiar client/server mode. It is based on the Java, JDBC, and SQL standards, making code developed more portable to standards-compliant databases.

Apache MINA is a network application framework which helps users develop high performance and high scalability network applications easily. It provides an abstract, event-driven, asynchronous API over various transports such as TCP/IP and UDP/IP via Java NIO.

Nutch is open source web-search software. It builds on Lucene Java and Hadoop, adding web-specifics, such as a crawler, a link-graph database, parsers for HTML and other document formats, etc.

Commons CLI provides a simple API for presenting, proecessing and validating a command line interface.

Velocity is a Java-based template engine. It permits anyone to use a simple yet powerful template language to reference objects defined in Java code. When Velocity is used for web development, Web designers can work in parallel with Java programmers to develop web sites according to the Model-View-Controller (MVC) model, meaning that web page designers can focus solely on creating a site that looks good, and programmers can focus solely on writing top-notch code. Velocity separates Java code from the web pages, making the web site more maintainable over its lifespan and providing a viable alternative to Java Server Pages (JSPs) or PHP.

Apache Lucene is a high-performance, full-featured text search engine library written entirely in Java. It is a technology suitable for nearly any application that requires full-text search, especially cross-platform.