Generator error: uncaught exception ?no classifier?

I'm creating a language to generate documents with MPS 2018.3.5.

I created a Runtime solution to import Apache POI (4.1.0) and I imported this solution to the generator module.

this is the code I'm working on:

Why do I have this exception "?no classifier?" ? Other methods seem are working.

Moreover, if I click on "Rebuild Solution", on the sandbox, I obtain these errors:

Someone can help? I'm stuck and I don't know what to do. Really thank you in advance.


Is the POI solution added as a runtime solution to BandoLanguage? (In BandoLanguage properties, on the Runtime tab).


Hi, first of all, thank you for the answer.

I think that not because I added the solution from the project as "New Solution".

There is a way to add a Runtime Solution to an existing project?


Runtime solutions are added to a language, not the project. On the Runtime tab:


Hi, adding this:

the exceptions on the Sandbox after click on "Rebuild Solution" disappear. However the error on the generator is still there.


Stupid question: have you tried rebuilding the entire project?

Another stupid question: have you added the POI JAR to the Libraries on the Java tab of the POI solution?


Hi, yes, I rebuilt it many times and I also add the POI jars to the Libraries on the Java tab . 

If I click on "Preview Generated Text", I can see the "script" generated as a java class. 

There is a way to execute this code in order to obtain the ".docx" file directly? 

Really thank you for the patience.



Looks like you're doing everything right and it should work. The only suggestion I have is to go through the documentation: or Federico Tomassetti's guide:

You can also try invoking your code from the MPS console to see whether it works or you get some reasonable error.


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