Amiba is a Gene Expression Programming (GEP) framework for Java. GEP is, like genetic algorithms, a branch of evolutionary computing. The framework separates the process of evolution from the process of interpretation of the chromosome, allowing the use of various schemes. For example, graphs may be used as terminals and graph operations as operators in the chromosome instead of the usual double precision numbers. It implements mutation, transposition, and recombination. Options and rates are easily configured through an XML file. A mechanism to load fitness cases in bulk is also provided.
Apache ActiveMQ is a popular and powerful message broker and enterprise integration patterns provider. Apache ActiveMQ is fast, supports many cross language clients and protocols, comes with easy-to-use enterprise integration patterns and many advanced features, while fully supporting JMS 1.1 and J2EE 1.4.
Apache Cayenne is a persistence framework that provides object-relational mapping (ORM) and remoting services. It has a wealth of unique and powerful features and can address a wide range of persistence needs. Cayenne seamlessly binds one or more database schemas directly to Java objects, managing atomic commit and rollbacks, SQL generation, joins, sequences, and more. With Cayenne's Remote Object Persistence, those Java objects can even be persisted out to clients via Web Services. With native XML serialization, objects can be even further persisted to non-Java clients.
Apache XML Graphics Commons is a library that consists of several reusable components used by Apache Batik and Apache FOP. Many of these components can easily be used separately outside the domains of SVG and XSL-FO. You will find components such as a PDF library, an RTF library, Graphics2D implementations that let you generate PDF and PostScript files, and much more.
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.