Apache Qpid is a messaging broker that implements the latest AMQP specification, providing transaction management, queuing, distribution, security, management, clustering, federation, heterogeneous multi-platform support, and much more. It is extremely fast and aims to be 100% AMQP Compliant.
Apache Rivet is a system for creating dynamic Web content via a programming language integrated with Apache Web Server. It is designed to be fast, powerful and extensible, consume few system resources, be easy to learn, and to provide the user with a platform that can also be used for other programming tasks outside the web (GUIs, system administration tasks, text processing, database manipulation, XML, etc.). It is similar to PHP, except that it uses Tcl, and provides both HTML/Tcl pages as well as pure Tcl pages to aid the programmer in separating logic and presentation when necessary.
Solr is an enterprise search platform from the Apache Lucene project. Its major features include powerful full-text search, hit highlighting, faceted search, dynamic clustering, database integration, and rich document (e.g. Word and PDF) handling. Solr is highly scalable, providing distributed search and index replication, and it powers the search and navigation features of many of the world's largest internet sites. Solr is written in Java and runs as a standalone full-text search server within a servlet container such as Tomcat. Solr uses the Lucene Java search library at its core for full-text indexing and search, and has REST-like HTTP/XML and JSON APIs that make it easy to use from virtually any programming language. Solr's powerful external configuration allows it to be tailored to almost any type of application without Java coding, and it has an extensive plugin architecture when more advanced customization is required.
Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
Synapse is an ESB engine and XML router built completely on open standards. It is a mediation framework for XML messages and Web services that allows messages flowing through, into, or out of an organization to be mediated, including aspects such as logging, service lookup, performance mediation, versioning, failover, monitoring, fault management, and tracing.
Apache uimaFIT provides Java annotations for describing UIMA components which can be used to directly describe the UIMA components in Java code without the need for traditional UIMA XML descriptors. This greatly simplifies refactoring a component definition (e.g., changing a configuration parameter name). It also makes it easy to instantiate UIMA components without using XML descriptor files by providing convenient factory methods. It is ideal for testing UIMA components because the component can be easily instantiated and invoked without requiring a descriptor file to be created first.
ApacheDS is an LDAP and X.500 experimentation platform. Its backend subsystem and frontend are separable and independently embeddable. It provides a server side JNDI LDAP provider that directly interacts with the backend storage. It is powered by SEDA (Staged Event-Driven Architecture), which can handle large amounts of concurrency.
Apollo is an open-source developer test skeleton toolkit for Java Web Start/JNLP. It lets you turbo-charge Web Start apps without Web Start to speed up your compile/run/test/debug/goof-off cycle, avoiding the hassle of stuffing, signing, uploading, or downloading your jars every time you rearrange a comma in your source code.
AppFuse is an application for "kickstarting" Web application development. It allows you to execute a single ant task to create a skeleton application based on Struts, Spring, and Hibernate running on Tomcat and MySQL. It uses Ant, XDoclet, Spring, Hibernate (or iBATIS), JUnit, jMock, StrutsTestCase, Canoo's WebTest, Struts Menu, Display Tag Library, OSCache, JSTL, and Struts. (Spring MVC, WebWork, Tapestry and JSF are also options.)