If you know basic Java and JPA you're already an OpenXava developer, you don't need any more to create complete applications. The OpenXava bundle is prepared for a rapid startup.
Modern web Single-Page Applications (SPA). List mode with paging, ordering, filtering, adding / removing / moving columns, PDF reports, export/import to Excel, cards format, charts, etc. Detail mode with tabs, frames, dialogs, editors for references and collections, responsive layout, maps, discussion threads, photo gallery, file upload, etc.
In addition to the classic web user interface for desktop you can get a mobile user interface for your application from the same code.
Browsers: Chrome, Firefox, Edge and Safari. Databases: Any supported by Hibernate, that is Oracle, DB2, AS/400, Informix, PostgreSQL, MySQL, MS SQL Server and practically all relational databases. Operating systems: Any with Java 8 (or better) support, that is Windows, Linux, Mac, Unix, AS/400, z/OS, etc. Application servers: Any with support for Servlets 3.0 (or better), including Tomcat, JBoss, WebSphere, Glassfish, WebLogic, etc. Enterprise portals: Any with JSR-168 or JSR-286 support including WebSphere Portal and Liferay.
The first production applications developed with OpenXava were for AS/400, using the AS/400 as the database with the application server in Linux or Windows, or even running the OpenXava applications inside the AS/400 (using WebSphere). In all cases the OpenXava applications used the tables designed by the RPG programmers as is, so the RPG programs still could work against the same data. Currently, many public administrations and banks around the world use OpenXava applications against AS/400 in production. It means that OpenXava is optimized to work nicely against the AS/400, moreover the team behind OpenXava has the know-how to face mapping AS/400 databases with Java technology, not so easy because RPG programmers do not use foreign keys, nulls, they use overlapped fields to chain different tables, fixed-length fields, and many other non-relational style practiques.
LGPL license that allows you to develop commercial applications without paying any fees.
The standard labels and messages included in OpenXava are in English, Spanish, German, French, Chinese, Russian, Japanese, Portuguese, Catalan, Indonesian, Italian, Polish, Serbian and Swedish. Moreover, it's pretty easy to add a new language.
250,000 downloads. 60 authors. Thousands of threads in the forums. Hundreds of applications developed. Hundreds of professionals in LinkedIn with OpenXava experience.
Complete Reference Guide in English, French, Russian, Chinese and Spanish. Free online course in English and Spanish where an invoicing application is developed from scratch. Book in English and Spanish available from Amazon. Hundreds of videos on YouTube.
Free support in community forums, though they have thousands of threads all questions are answered. Moreover, there is professional support available.
Thus you can migrate your current Java code easily to OpenXava, and vice versa. You can use any Java tool for OpenXava. Your Java developers are already OpenXava developers. OpenXava supports: JSR-338, JSR-317, JSR-303, JSR-330, JSR-220, JSR-153, JSR-311, JSR-339, JSR-370, JSR-168 and JSR-286.
Many developers have integrated their OpenXava applications with other enterprise technologies and tools such as Talend, Bonita Open Solution, Ehcache, Spring Framework, Spring Security, Spring Scheluding, Quartz, Groovy, IntelliJ, Maven, Grafana, Pentaho, Docker, etc.
6 releases/year, half of them maintenance releases (just with bug fixes). Since 2005.