At the Quick start http://openjdk.java.net/projects/jigsaw/quick-start a line is missing. Just before making this change to the module-info.java of org.astro module: $ cat src/org.astro/module-info.java module org.astro { // exports org.astro; } It is missing the command to recompile that file: javac --module-path mods -d mods/org.astro/ src/org.astro/module-info.java May be it can be part of: $ javac --module-path mods -d mods/com.greetings \ src/com.greetings/module-info.java src/com.greetings/com/greetings/Main.java Regards, Martín