How to use 3rd party library in Java9 module?

Question

I have some java9 module that uses 3rd party library that is not Java9 module, just a simple utility jar.

However, the compiler complains that it can\'t find a packa

Answer 1

To put it in simple steps, to use a 3rd party jar (e.g. log4j-api-2.9.1.jar below) in your module:-

1. Execute the descriptor command of jar tool

    jar --file=/path/to/your/jar/log4j-api-2.9.1.jar --describe-module
   

   This would provide you an output similar to

   No module descriptor found. Derived automatic module. log4j.api@2.9.1 automatic

2. In your module descriptor file, declare a requires to that module name as:-

    module your.module {
        requires log4j.api;
    }
   

That's it.