Hey there,
I'm currently preparing a Java upgrade of my Tomcat application from 17
to 25. In JDK 24 (https://openjdk.org/jeps/472) a new runtime warning
was added if a class tries to use native methods, which is the the case
in one of my libraries.
I'm currently trying to figure out whether I can avoid this warning
without having to resort to `|--enable-native-access=ALL-UNNAMED|` which
would enable native access for the entire class-path (and not
selectively only for the part that needs it). The library performing the
native access is an automatic module, so if I started the JVM with it on
the module path I should be able to say
`|--enable-native-access=my.module|` instead. The trouble is of course
that my JVM only starts running the tomcat classes, and tomcat will then
later load my classes (i.e. tomcat decides where the classes should go,
not `java`).
I have only found one question on the users list from someone struggling
with a similar Issue
(https://marc.info/?l=tomcat-user&m=157356882531534&w=2), but
unfortunately that thread go into much detail.
So my concrete questions are:
1. Am I correct in saying that there is no way to make the tomcat webapp
classloader load (some of) my classes onto the module-path instead of
the class-path? And if that is the case, is this a deliberate decision
(or just not implemented yet) by tomcat or are there other, bigger reasons?
2. Could I circumvent this by including my JPMS modules in the `java`
command line which would otherwise only start the tomcat classes (As I
understand I should be able to access them from the webapp if I enabled
the delegate option in the loader, see
https://tomcat.apache.org/tomcat-10.1-doc/config/loader.html)? Then I
suppose I should be able to restrict native access to this module, but
I'm wondering if that would break something else in tomcat/my webapp?
3. Is there any other way except giving ALL-UNNAMED access to native
access (and all of the other restricted Java features which may be in
use by parts of my webapp) that I'm missing? It just seems like a bad
idea to me so I thought that maybe I'm missing something. (I know that
this is how java always used to work, but it's clearly not the direction
Java is moving in right now)
Thanks!
Best,
Christian
