documentation support for servlet 3.1

[andradefil]

Jetty Version
jetty 12.1

Jetty Environment
jetty 12 ee8

Java Version
17

Question
Is Java Servlet 3.1 really supported by Jetty 12? Jetty 10 dropped Servlet 3.1 in favor of 4.0, yet the Jetty 12 downloads page lists 3.1 as supported again.

https://jetty.org/download.html#version-history

There is no Java EE 7 environment, and the dependency graph shows that the Jetty EE8 package depends on Servlet 4.0

[joakime]

The question comes down to ...

What's the difference between Servlet 3.1 (EE7) vs Servlet 4.0 (EE8)?

1. Servlet 4.0 introduced a new HTTP/2 Server Push feature PushBuilder (now deprecated by the HTTP/2 spec, many browsers don't support it anymore)
2. Servlet 4.0 introduced a new Mapping APIs (See HttpServletMapping).
3. Servlet 4.0 bumped the minimum Java version to 8.
4. Servlet 4.0 is now legally owned by Eclipse Jakarta (no longer Oracle / Sun)

So aside from a few NEW APIs, there's no functional difference between Servlet 3.1 (EE7) and Servlet 4.0 (EE8).
If you only wrote for Servlet 3.1 (EE7), or have a legacy webapp on Servlet 3.1 (EE7), it will be 100% compatible on Servlet 4.0 (EE8).

Go ahead, use Jetty 12, with the EE8 environment with your legacy webapp without fear.

[andradefil]

@joakime thank you for the reply. We use Jetty WebServer as part of Datomic cloud database infrastructure. We are evaluating whether to strategically stay with Servlet 4.0 (EE8) while upgrading from Jetty 9 to Jetty 12. Do you know if the Jetty team has any plans to deprecate support for Java EE 8 any time soon?

[sbordet]

Java EE 8 is old, and the EE javax.* packages are being phased out since years now.

Since you're upgrading from Jetty 9 to 12, I think it's a good chance to remove the technical debt you have with your dependency on javax, and move to Jakarta EE instead.

There are tools that can mechanically update from javax.* to jakarta.*.

There are few incompatibilities that have been introduced in Jakarta EE 10 (with respect to Jakarta EE 9), but are typically edge cases and likely your application does not rely on those edge cases, so you have very good chances that after moving to jakarta.* your application will work fine.

We will keep around Java EE 8 for some more time, I guess until Java 8 is around, but I would not recommend you to move to a modern Jetty server version but keep an old EE technology -- eventually you will have to fill that technical debt, and doing it now is likely the best option.