To use HelloApp, we need to export the package com.packt.helloapp from the helloApp module and include the helloApp module in the helloClient module:
module com.packt.helloapp { exports com.packt.helloapp;}module com.packt.hello.client { requires com.packt.helloapp;}
From the preceding code, the first module descriptor, the exports keyword, indicates that packages are available to export to other modules. If a package is explicitly exported, then it is only accessible by other modules. If in a same module some packages are not exported, then it cannot be accessed by other modules.
The second module descriptor uses the requires keyword to indicate that the module is dependent on the com.packt.helloapp
