OpenXava

• Why to use OpenXava if we have Spring, Hibernate, JSF, EJB3 and so on?
• How scalable it is?
• What type of users manager system and navigation could you use with OpenXava?
• What Application Servers are supported?
• What Java Portals are supported?
• What Development Tools can be used?
• What JDK need to run?
• What licence type has OpenXava?

Why to use OpenXava if we have Spring, Hibernate, JSF, EJB3 and so on?

Nowadays we live great times. It's true that Spring, Hibernate, JSF and EJB3 are far better than J2EE 1.4. All these frameworks and technologies are good (in fact OpenXava uses some of them), but if you need to develop business application the amount of code to write continues being big, and the productivity is low comparing with other technologies (Visual Basic, 4GL, Delphi, RPG, etc).
OpenXava simply has a higher level of abstraction in order to obtain a simple and easy way to develop business application with Java EE/J2EE in a Object Oriented fashion.
If you do not believe me. Try it. See the demo applications, see the code for them, try to develop some of them with your favourite framework, and compare  yourself.

How scalable it is?

OpenXava generates a standard Java EE/J2EE application, hence it's as scalable as Java EE/J2EE.
OpenXava uses EJB3 JPA, Hibernate or EJB CMP2 for persistence, and some session scope state at servlets level. The OpenXava code is good, but when you write your own code you must to be wise in order to obtain a good performance, specially in batch processes, but this is an issue of J2EE not OpenXava.

What type of users manager system and navigation could you use with OpenXava?

The modules generated by OpenXava are JSR-168 portlets, hence they are deployabled in any compliant Java Portal with its own security and navigation features. 
OpenXava site is powered by Liferay Portal, therefore in this case the Liferay security is used, but you can choose another portal or create your own security and navigation framework for OpenXava modules.

What Application Servers are supported?

OpenXava has been tested with:

• Tomcat 5.5
• JBoss 4.0.x and 3.2.x
• WebSphere 6.1, 6.0, 5.1 

Any Servlet 2.3 compliant container can execute OpenXava applications.
If you want use EJB (optional in v2 or greater) you need at least a J2EE 1.3 application server.
If you want to use EJB3 JPA you need an application server with Java 5 support (a Java EE 5 server is not required).
WebSphere 5.0 works fine with OpenXava 1.2.1, but it's not tested since OpenXava 2.

What Java Portals are supported?

Any JSR-168 compatible portal. Although the next ones are tested:

• Apache JetSpeed 2
• WebSphere Portal 5.1 and 6.0
• Liferay 4.1.x, 4.2.x and 4.3.x
• Stringbeans

What Development Tools can be used?

The downloaded OpenXava zip file has a configured workspace to use with Eclipse. OpenXava is not using Eclipse resources but it's based in the Ant Tool (which it's open source). You can use whatever IDE that you want without problem or also from command lines.

What JDK needs to run?

The OpenXava works with JDK 1.4.2, JDK 5.0 and JDK 6.0.
If you want to use EJB3 JPA you need at least Java 5.
JDK 1.3.1 works fine with OpenXava 1.2.1, but it's not tested since OpenXava 2.

What licence type has OpenXava?

LGPL. You can use OpenXava to develop every comercial project than you want. The unique forbidden thing is developing your own comercial version of OpenXava.