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Home » Modeling » TMF (Xtext) » Problem while adding libraries to xtext Project(The building process runs fine, but when executing, eclipse generates error)

Problem while adding libraries to xtext Project [message #1748363]

Tue, 22 November 2016 08:21

Eclipse User

Firstly, I created an xtext project using default values (with the simple Greetings grammar which comes as an example).

I created then a .java file with some code (that can be seen below) and added it to the validation folder.

I have loaded some jars to the build path as I would do in a normal Java Project. If I run my specific java file as a standalone it will load the libraries and run the code. The java file is quite simple:

import org.semanticweb.owlapi.apibinding.OWLManager;
import org.semanticweb.owlapi.model.OWLOntologyCreationException;
import org.semanticweb.owlapi.model.OWLOntologyManager;
import org.xtext.example.mydsl.myDsl.Greeting;

public static void main(String[] args){
    Greeting hey = null;
    try {
        test(hey);
    } catch (OWLOntologyCreationException e) {
        e.printStackTrace();
    }
}

public static void test(Greeting imp) throws OWLOntologyCreationException {
    OWLOntologyManager manager = OWLManager.createOWLOntologyManager();
    System.out.println("success!");     
}

However, if a call the "test" function from the .xtend validator file, it will generate this error:

java.lang.NoClassDefFoundError: org/semanticweb/owlapi/model/OWLOntologyCreationException
at org.xtext.example.mydsl.validation.MyDslValidator.checkGreetingStartsWithCapital(MyDslValidator.java:24)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
/* (has some more "at" in the middle) */
Caused by: java.lang.ClassNotFoundException: org.semanticweb.owlapi.model.OWLOntologyCreationException cannot be found by org.xtext.example.mydsl_1.0.0.qualifier
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:461)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:372)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:364)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:161)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 32 more

When it mentioned "cannot be found by org.xtext.example.mydsl_1.0.0.qualifier" I assumed the problem was in the manifest, but I've tried adding the libraries to the manifest in every way possible but to no avail.

Re: Problem while adding libraries to xtext Project [message #1748430 is a reply to message #1748363]

Wed, 23 November 2016 02:04

Eclipse User

Have you tried adding the org.semanticweb.owlapi... to the manifest as dependencies ?

and I think the code of your validator would be helpful

Re: Problem while adding libraries to xtext Project [message #1748438 is a reply to message #1748430]

Wed, 23 November 2016 03:34

Eclipse User

The dependency should be resolved at runtime as well, so it should be added to the manifest. Something like this:

 Bundle-ClassPath: lib/yourDependency.jar,
 lib/anotherDependency.jar,
 .

You can also configure it from the manifest editor's Runtime page > Classpath section. Hope this helps.

Re: Problem while adding libraries to xtext Project [message #1748439 is a reply to message #1748363]

Wed, 23 November 2016 03:39

Eclipse User

Not really an Xtext problem here: The error says the respective class is not on the classpath.

In which library is it? How did you add that library to the classpath (MANIFEST, .classpath)? Does it depend on further classes from other libraries that need to be added to the classpath as well?

Re: Problem while adding libraries to xtext Project [message #1748519 is a reply to message #1748363]

Wed, 23 November 2016 17:26

Eclipse User

Thanks everyone, I was inserting the semantic libraries in build.properties as a folder, when I inserted each Jar separately, it worked. Very Happy

Re: Problem while adding libraries to xtext Project [message #1856861 is a reply to message #1748363]

Thu, 05 January 2023 13:18

Eclipse User

Hello, Im having the same problem while running the jar file I created

Should I manually add the libraries in the manifest of the jar? and what libraries?

Attachment: Captura de ecrã_20230105_201558.png
(Size: 10.68KB, Downloaded 102 times)

Re: Problem while adding libraries to xtext Project [message #1856885 is a reply to message #1856861]

Sat, 07 January 2023 05:00

Eclipse User

There should be exports for the stuff you want too (runtime tab in manifest editor )
You also need to make sure the jar is packaged (build.properties)

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