The package new namespace is now jakarta, instead of the erstwhile javax, and all the specification APIs have been moved to the jakarta namespace; which is a very significant update that will open the door for the next evolution of cloud native technologies.
Jakarta EE is the successor to Java EE, which as the former enterprise edition platform of Java, was developed by a team led by Oracle. But, Oracle announced in February 2018 that it was transitioning Java EE development over to the Eclipse Foundation in order to open up platform.
Jakarta EE 9 as a Platform for Cloud native Technologies
Jakarta EE 9 offers a divergence view from previous platform release strategies, with the namespace switch serving as a break change for the enterprise Java ecosystem.
Along with the release of Jakarta EE 9, the Eclipse Foundation also announced the certification of the GlassFish 6.0.0 application server, which is the first compatible implementation of Jakarta EE 9. And other implementations like the Apache Tomcat Java application server are expected to move over to Jakarta EE 9 starting from early next year.
Now, the community working on each Jakarta EE specification will have the flexibility to deliver as much specification releases as possible to meet the requirements. And developers and enterprises that require the advances in technology with a particular Jakarta EE specification such as Servlet will no longer have to wait for full platform release to get started with those advances.
As the Jakarta EE community expects to offer full platform releases often than in the past, they will share more details about the release strategy as it makes progress.
How to get Started with Jakarta EE 9
If you wish to migrate to Jakarta EE 9, the Eclipse transformer tooling project offers utilities (cli, maven plugin ) to help you upgrade the codes in batch mode, as currently Jakarta EE 9 rules is still under development.
And note that the Jakarta EE product vendors are still moving to the new Jakarta EE 9 platform, such as Glassfish v6.0.0.M1 which is now available for testing Jakarta EE 9. WildFly 21 and Payara platform 6 will also provide compatible products in the coming months. While Open Liberty 220.127.116.11 beta offer partial web application support of Jakarta EE 9, Jetty 11.0.0-alpha0 and Apache Tomcat 10.0-M6 have announced Servlet support of Jakarta EE 9 in their respective milestone products.