NoSuchElementExeption for languages fi,et,lt

[Integer-Ctrl]

Describe the bug

Inside server.default.properties the list of enabled languages can be specified. The languages fi,et,lt are causing a NoSuchElementException on server start via run server.

Expected behaviour

A successful build, as with all the other languages.

Environment

Please fill out or post:

• Extraction: (commit hash): 9e66903
• OS: Pop!_OS 22.04 LTS
• Java SDK Version (java --version): openjdk version "1.8.0_442" | OpenJDK Runtime Environment Corretto-8.442.06.1 (build 1.8.0_442-b06) | OpenJDK 64-Bit Server VM Corretto-8.442.06.1 (build 25.442-b06, mixed mode)
• Maven version (mvn --version): Java version: 1.8.0_442, vendor: Amazon.com Inc., runtime: home/fhofer/.sdkman/candidates/java/8.0.442-amzn/jre | Default locale: en_US, platform encoding: UTF-8 | OS name: "linux", version: "6.17.9-76061709-generic", arch: "amd64", family: "unix"

To reproduce

Add one or more of the three languages to sever.default.properties and run redeploy-server. For example:
languages=wikidata,en,de,fr,es,it,pt,ru,ja,ko,ar,hi,nl,sv,pl,uk,cs,sk,sl,sr,hr,ro,bg,hu,tr,el,fi,et,lv,lt,ga,cy,eo,ca,gl,eu,be,az,hy,am,bn,ur,vi,id,mk,commons

Additional context & logs

Error occurring when using languages=wikidata,en,de,fr,es,it,pt,ru,ja,ko,ar,hi,nl,sv,pl,uk,cs,sk,sl,sr,hr,ro,bg,hu,tr,el,fi,et,lv,lt,ga,cy,eo,ca,gl,eu,be,az,hy,am,bn,ur,vi,id,mk,commons

$ ./redeploy-server
[ ... ]
WARNING: LOADING MAPPINGS NOT FROM SERVER, BUT FROM LOCAL FILE [../mappings/Mapping_fr.xml] - MAY BE OUTDATED - ONLY FOR TESTING!
java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at scala_maven_executions.MainHelper.runMain(MainHelper.java:164)
        at scala_maven_executions.MainWithArgsInFile.main(MainWithArgsInFile.java:26)
Caused by: java.util.NoSuchElementException: no mapping namespace for language fi
        at org.dbpedia.extraction.server.ExtractionManager$$anonfun$3.apply(ExtractionManager.scala:155)
        at org.dbpedia.extraction.server.ExtractionManager$$anonfun$3.apply(ExtractionManager.scala:155)
        at scala.collection.MapLike$class.getOrElse(MapLike.scala:128)
        at scala.collection.AbstractMap.getOrElse(Map.scala:59)
        at org.dbpedia.extraction.server.ExtractionManager.loadMappingPages(ExtractionManager.scala:155)
        at org.dbpedia.extraction.server.ExtractionManager$$anonfun$loadMappingPages$1.apply(ExtractionManager.scala:146)
        at org.dbpedia.extraction.server.ExtractionManager$$anonfun$loadMappingPages$1.apply(ExtractionManager.scala:146)
        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
        at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
        at scala.collection.mutable.WrappedArray.foreach(WrappedArray.scala:35)
        at scala.collection.TraversableLike$class.map(TraversableLike.scala:245)
        at scala.collection.AbstractTraversable.map(Traversable.scala:104)
        at org.dbpedia.extraction.server.ExtractionManager.loadMappingPages(ExtractionManager.scala:146)
        at org.dbpedia.extraction.server.DynamicExtractionManager.<init>(DynamicExtractionManager.scala:39)
        at org.dbpedia.extraction.server.Server.<init>(Server.scala:42)
        at org.dbpedia.extraction.server.Server$.main(Server.scala:203)
        at org.dbpedia.extraction.server.Server.main(Server.scala)
        ... 6 more
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  4.857 s
[INFO] Finished at: 2026-01-27T11:51:55+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal net.alchim31.maven:scala-maven-plugin:3.2.0:run (default-cli) on project server: wrap: org.apache.commons.exec.ExecuteException: Process exited with an error: 240 (Exit value: 240) -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

[Asif-rehman012]

change logic to :

mappingNamespaces.get(language) match {
case Some(ns) => loadMappings(ns)
case None =>
logger.warn(s"No mapping namespace for language $language, skipping.")
}

if that doesn't work do :

Validation at startup (Before loading mappings):

val missing = languages.filterNot(mappingNamespaces.contains)
require(missing.isEmpty,
s"Missing mapping namespaces for: ${missing.mkString(", ")}")

If this approach is acceptable, I can submit a PR
to handle missing mapping namespaces gracefully.

[Integer-Ctrl]

Hi @Asif-rehman012!

It is always good practice to handle exceptions. I haven't viewed the code, so I don't know if your changes are applicable, but overall, this sounds alright to me.

However, besides catching this exception, do you know why these languages are missing? It would be even better to fix the issue or at least find out why these languages are missing.

[Asif-rehman012]

As i checked ,the issue is caused by missing DBpedia namespace fields for fi/et/lt in addonlangs.json. The Scala code correctly loads namespaces from this file, but these languages are defined without dbpediaDomain/dbpediaUri, which leads to the runtime exception