WebSphere

OpenXava applications are not been tested for WebSphere Application Server 8.5 or better.
Support for WebSphere 8.0 was dropped in OpenXava 6.1. WebSphere 8.0 and WebSphere Portal 8.0 are supported in OpenXava until OpenXava 6.0.2.
Support for WebSphere 6.1 was dropped in OpenXava 5.0. WebSphere 6.1 and WebSphere Portal 6.1 are supported in OpenXava 4.x.
Here some screenshots of an OpenXava application in WebSphere Portal:

Ant targets for WebSphere 8 and WebSphere Portal 8 (not needed since OpenXava 5.3.1)

Since OpenXa 5.3.1 the regular ant targets to create wars and portlets applications work with WebShere 8
You have to define in your build.xml the next ant targets:
<target name="createWebSphere8War">
    <ant antfile="../OpenXava/build.xml" target="createWebSphere8War"/>
</target>
 
<target name="generateWebSpherePortal8Portlets">
    <ant antfile="../OpenXava/build.xml" target="generateWebSpherePortal8Portlets"/>
</target>
Use the above ant targets to deploy on WebSphere 8 and WebSphere Portal 8.

Class loading (not needed in WebSphere Portal 8)

OpenXava uses the libraries commons-codec and jakarta-poi that are also included in WebSphere (8 and 6.1). The problem is that the ones included in WebSphere (even in version 8) are older than the ones included in OpenXava. This can produce some problems when your code uses some features of OpenXava that use some of these libraries.
You have two solutions:

Servlet 2.4 syntax forced for web.xml in WebSphere Portal 8

It means that you cannot use display-name and description at servlet level. Therefore, in your own servlets you have to change this:
<servlet>
  <servlet-name>testServlet</servlet-name>
  <display-name>Test servlet</display-name>
  <description></description>
  <servlet-class>org.openxava.test.servlets.TestServlet</servlet-class>
</servlet>
By this:
<servlet>
  <servlet-name>testServlet</servlet-name>
  <servlet-class>org.openxava.test.servlets.TestServlet</servlet-class>
</servlet>