Handling possible errors

Here are some possible errors you could run into when following the steps we previously outlined, along with some solutions:

1. Error during compilation:

      javac: invalid flag: --module-source-path 

This is probably because you haven't switched to JDK 9 and are still using the Java 8 compiler. The --module-source-path option has been newly introduced to  javac as of version 9.

1. Error during compilation:

      error: module not found: packt.addressbook 

This error is because the Java compiler is unable to find the module-info.java file. Make sure it is in the right directory path.

1. Error during runtime:

      Error occurred during initialization of VM 
      java.lang.module.ResolutionException: Module packt.addressbook
      not found 

This error indicates that the module file is not available in the module path provided. Make sure the path is correctly specified and that the packt.addressbook folder contains the compiled module-info.class file.