This is a work in progress, a first attempt to collect development related information . Here you will find application frameworks and how Apache Geronimo integrates them as well as best practices for developing applications.

Application frameworks

Spring - http://www.springframework.org/
Spring is a layered Java/J2EE application framework, based on code published in Expert One-on-One J2EE Design and Development.

Struts - http://jakarta.apache.org/struts/
The core of the Struts framework is a flexible control layer based on standard technologies like Java Servlets, JavaBeans, ResourceBundles, and XML, as well as various Jakarta Commons packages. Struts encourages application architectures based on the Model 2 approach, a variation of the classic Model-View-Controller (MVC) design paradigm.

Turbine - http://jakarta.apache.org/turbine/
Turbine is a servlet based framework that allows experienced Java developers to quickly build secure web applications. Turbine is an excellent choice for developing applications that make use of a services-oriented architecture. Some of the functionality provided with Turbine includes a security management system, a scheduling service, XML-defined form validation server, and an XML-RPC service for web services. It is a simple task to create new services particular to your application.

Tapestry - http://jakarta.apache.org/tapestry/
Tapestry is a powerful, open-source, all-Java framework for creating leading edge web applications in Java. Tapestry reconceptualizes web application development in terms of objects, methods and properties instead of URLs and query parameters. Tapestry is an alternative to scripting environments such as JavaServer Pages or Velocity. Tapestry goes far further, providing a complete framework for creating extremely dynamic applications with minimal amounts of coding.

WebWork - http://www.opensymphony.com/webwork/
WebWork is a web application framework for J2EE. It is based on a concept called "Pull HMVC" (Pull Hierarchical Model View Controller).

Cocoon - http://cocoon.apache.org/
Apache Cocoon is a web development framework built around the concepts of separation of concerns and component-based web development. Cocoon implements these concepts around the notion of 'component pipelines', each component on the pipeline specializing on a particular operation. This makes it possible to use a Lego(tm)-like approach in building web solutions, hooking together components into pipelines without any required programming.

Maverick - http://mav.sourceforge.net/
Maverick is a Model-View-Controller (aka "Model 2") framework for web publishing using Java and J2EE. It is a minimalist framework which focuses solely on MVC logic, allowing you to generate presentation using a variety of templating and transformation technologies.

Echo - http://www.nextapp.com/products/echo/
Echo is a framework for developing object-oriented, event-driven Web applications. Echo removes the developer from having to think in terms of "page-based" applications and enables him/her to develop applications using the conventional object-oriented and event-driven paradigm for user interface development.

Persistence layers

Hibernate - http://www.hibernate.org/
Hibernate is a powerful, ultra-high performance object/relational persistence and query service for Java. Hibernate lets you develop persistent objects following common Java idiom - including association, inheritance, polymorphism, composition and the Java collections framework. Extremely fine-grained, richly typed object models are possible. The Hibernate Query Language, designed as a "minimal" object-oriented extension to SQL, provides an elegant bridge between the object and relational worlds. Hibernate is now the most popular ORM solution for Java.
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OJB - http://db.apache.org/ojb/
ObJectRelationalBridge (OJB) is an Object/Relational mapping tool that allows transparent persistence for Java Objects against relational databases.

Torque - http://db.apache.org/torque/
Torque is a persistence layer. Torque includes a generator to generate all the database resources required by your application and includes a runtime environment to run the generated classes.

Castor - http://castor.exolab.org/
Castor is an open source data binding framework for Java. It's basically the shortest path between Java objects, XML documents and SQL tables. Castor provides Java to XML binding, Java to SQL persistence, and then some more.

JDO - http://java.sun.com/products/jdo/
The Java Data Objects (JDO) API is a standard interface-based Java model abstraction of persistence, developed as Java Specification Request 12 (JSR 12) under the auspices of the Java Community Process. If you are an application programmer, you can use JDO technology to directly store your Java domain model instances into the persistent store.

TJDO - http://tjdo.sourceforge.net/
TriActive JDO (TJDO) is an open source implementation of Sun's JDO specification (JSR 12), designed to support transparent persistence using any JDBC-compliant database. TJDO has been deployed and running successfully in many commercial installations since 2001.