Modular Programming in Java 9

Examining module resolution in action

There's a new command option added to Java that prints out debug information that describes the module resolution process. You can activate it by passing the option --show-module-resolution. When passed this option, the java command prints out console messages for each step of the module resolution. You can use this to see the process that the runtime goes through to resolve all the modules, much like we did in the preceding exercise.

This is how you ran the command-line address book module in the previous chapter, without the flag:

$ java --module-path out -m packt.addressbook/packt.addressbook.Main

Here's how you run it with the module resolution diagnostics enabled:

$ java --show-module-resolution ...