I'm beginning to look at the JDK 9 impact on our source base. I'm trying to understand if we need to use any --add-modules switches for our code.
One example class is com.sun.net.httpserver.HttpServer. This is not in the default root module java.se, but is found at compile and runtime. I assume that this is because of the rule defining that "Every non-java.* module on the upgrade module path or among the system modules that exports at least one package, without qualification, is also a root." (from JEP 261).
Now if I try using the class with --limit-modules, I get results I do not understand:
$ java --limit-modules=java.se com.sun.net.httpserver.HttpServer
Error: Could not find or load main class com.sun.net.httpserver.HttpServer
Caused by: java.lang.ClassNotFoundException: com.sun.net.httpserver.HttpServer
and
$ java --limit-modules=java.se.ee com.sun.net.httpserver.HttpServer
Error: Main method not found in class com.sun.net.httpserver.HttpServer, please define the main method as:
public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application
If I run the latter with --show-module-resolution, I see:
bash-4.1$ /usr/java/jdk9/bin/java --limit-modules=java.se.ee --show-module-resolution com.sun.net.httpserver.HttpServer
root jdk.httpserver jrt:/jdk.httpserver
root java.se jrt:/java.se
root jdk.unsupported jrt:/jdk.unsupported
java.se requires java.datatransfer jrt:/java.datatransfer
java.se requires java.xml jrt:/java.xml
...
So my question is - what is different about the java.se.ee module that causes the extra root modules to be available? I cannot see anything in the java.se.ee module-info which would cause this.
Thanks
Richard