Suppose I have some library lib.jar for which I do not have the source code (or it is written in some non-Java language which is unaware of modules yet). lib.jar does not have module-info.class and I do not want to use it as an automatic module, so I would like to inject module-info.class into it.
I first generate module-info.java with the following command:
jdeps --generate-module-info . lib.jar
Suppose this generated something like that:
module lib {
exports package1;
exports package2;
}
Then I try to compile it but javac fails because the packages package1 and package2 do not exist:
> javac module-info.java
module-info.java:4: error: package is empty or does not exist: package1
Of course, I can create directories package1 and package2 with dummy classes in them, but is there some better approach?
Yes, this is possible with the --patch-module option. This option is most often used at runtime, but it also works at compile time:
javac --patch-module <module name>=<path to jar> module-info.java