Java 9 第三方模块«链接»，如何？，何时？ -> java.lang.NoClassDefFoundError

Question

Please do not provide solutions using Maven, Gradle… I look for a CLI solution only . No jlink-based solution as well.

Given Open_My_type_module-1.0.jar as a preexisting compiled Java 9 module:

module Open_My_type_module { // module-info.java
    exports Open_My_type_package;
    opens Open_My_type_package;
}

The code in this module only declares the following class:

Open_My_type_package.My_type

I reuse this module into another one as follows:

module Access_My_type_module { // module-info.java
    requires Open_My_type_module;
}

// Business code (for test only in a Main.java class):

Class<Open_My_type_package.My_type> c = Open_My_type_package.My_type.class;

Starting from the following structure:

THIRD_PARTY_MODULE >> Open_My_type_module-1.0.jar
src >> main >> java >> com >> X >> Access_My_type_package >> Main.java
src >> main >> java >> module-info.java

Compilation succeeds based the following line:

javac -d PRODUCTION_SOFTWARE --module-path THIRD_PARTY_MODULE src/main/java/com/X/Access_My_type_package/Main.java src/main/java/module-info.java

Next, before execution, I package my software as follows:

cd PRODUCTION_SOFTWARE
jar --create --verbose --file Access_My_type_module-1.0.jar --main-class com.X.Access_My_type_package.Main *

Packaging DOES NOT seem to « link » Open_My_type_module-1.0.jar in the final executable, but I check the inside of the packaged software:

jar --file=Access_My_type_module-1.0.jar --describe-module

Display (everything seems sound):

Access_My_type_module jar:file://./Access_My_type_module-1.0.jar/!module-info.class
requires Open_My_type_module
requires java.base mandated
contains com.X.Access_My_type_package
main-class com.X.Access_My_type_package.Main

Finally, execution fails with java.lang.NoClassDefFoundError from:

java --module-path THIRD_PARTY_MODULE -jar Access_My_type_module-1.0.jar

I believed that --module-path THIRD_PARTY_MODULE is enough to link Open_My_type_module-1.0.jar at execution time, but I keep the feeling that my packaging command is shaky. Beyond, I'm sure I've missed of a key issue about Java 9 modules… HELP WELCOME please!

Answer 1

Solution (below) is inspired from https://sites.google.com/a/athaydes.com/renato-athaydes/posts/guidetojava9-compilejarrun .

With Java modules, execution is better controlled using --module instead of -jar . So java --module-path THIRD_PARTY_MODULE --module Access_My_type_module works fine! Assumption: Access_My_type_module-1.0.jar must be located within THIRD_PARTY_MODULE along with Open_My_type_module-1.0.jar (for simplicity here). In short, java finds in the THIRD_PARTY_MODULE directory all the desired stuff. Please note that --module required the module name (ie, Access_My_type_module ) and NOT the jar file name! Please also note that Access_My_type_module-1.0.jar manifest has already been set up with a main class at packaging time... if not tell java which is the main class at execution time.