Java 9 modules and classpath hell: conflicting class names

Question

It is said that java 9 modules will solve classpath hell. However, I am thinking about the following situation: Module A uses modules B and C. Both modules will export a class with same name and package. How will the classloading issue be solved here?

Answer 1

This situation is forbidden in the Java 9 module system. If two modules in the same layer have the same package, Java 9 will fail at startup with an error:

java.lang.LayerInstantiationException:
    Package <package_name> in both module <moduleB_name> and module <moduleC_name>