Maven build fails (jar file and Protégé-Plugin aren't getting built)

[k00ni]

I am conducting a survey on OWL reasoners still usable in 2023 and would like to try out this reasoner. I ran mvn clean package (Ubuntu 20.04. with OpenJDK 11) but it gave me the following results (something with clingo?):

java.io.IOException: Cannot run program "clingo": error=2, file or folder not found
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1128)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1071)
	at org.semanticweb.wolpertinger.clingo.ClingoSolver.solve(ClingoSolver.java:53)
	at org.semanticweb.wolpertinger.clingo.ClingoModelEnumerator.enumerateModels(ClingoModelEnumerator.java:49)
	at org.semanticweb.wolpertinger.Wolpertinger.enumerateAllModels(Wolpertinger.java:318)
	at org.semanticweb.wolpertinger.WolpertingerTest.testSimple3ColoringHas24AnswerSets(WolpertingerTest.java:300)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at junit.framework.TestCase.runTest(TestCase.java:154)
	at junit.framework.TestCase.runBare(TestCase.java:127)
	at junit.framework.TestResult$1.protect(TestResult.java:106)
	at junit.framework.TestResult.runProtected(TestResult.java:124)
	at junit.framework.TestResult.run(TestResult.java:109)
	at junit.framework.TestCase.run(TestCase.java:118)
	at junit.framework.TestSuite.runTest(TestSuite.java:208)
	at junit.framework.TestSuite.run(TestSuite.java:203)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.apache.maven.surefire.junit.JUnitTestSet.execute(JUnitTestSet.java:95)
	at org.apache.maven.surefire.junit.JUnit3Provider.executeTestSet(JUnit3Provider.java:121)
	at org.apache.maven.surefire.junit.JUnit3Provider.invoke(JUnit3Provider.java:98)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
	at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
	at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)
Caused by: java.io.IOException: error=2, Datei oder Verzeichnis nicht gefunden
	at java.base/java.lang.ProcessImpl.forkAndExec(Native Method)
	at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:340)
	at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:271)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1107)
	... 33 more

and in the end:

testComplexConceptSubclassEntailment(org.semanticweb.wolpertinger.WolpertingerTest)  Time elapsed: 0.094 sec  <<< ERROR!
java.lang.NullPointerException
	at org.semanticweb.wolpertinger.Wolpertinger.isConsistent(Wolpertinger.java:523)
	at org.semanticweb.wolpertinger.Wolpertinger.isEntailed(Wolpertinger.java:583)
	at org.semanticweb.wolpertinger.Wolpertinger.isEntailed(Wolpertinger.java:529)
	at org.semanticweb.wolpertinger.WolpertingerTest.testComplexConceptSubclassEntailment(WolpertingerTest.java:350)

testUnsatifiabilityDueToClashInABoxAssertions(org.semanticweb.wolpertinger.WolpertingerTest)  Time elapsed: 0.072 sec  <<< ERROR!
java.lang.NullPointerException
	at org.semanticweb.wolpertinger.Wolpertinger.isConsistent(Wolpertinger.java:523)
	at org.semanticweb.wolpertinger.WolpertingerTest.testUnsatifiabilityDueToClashInABoxAssertions(WolpertingerTest.java:81)

testUnsatisfiabilityDuetoSimpleSubsumptionViolation(org.semanticweb.wolpertinger.WolpertingerTest)  Time elapsed: 0.067 sec  <<< ERROR!
java.lang.NullPointerException
	at org.semanticweb.wolpertinger.Wolpertinger.isConsistent(Wolpertinger.java:523)
	at org.semanticweb.wolpertinger.WolpertingerTest.testUnsatisfiabilityDuetoSimpleSubsumptionViolation(WolpertingerTest.java:111)

testUnsatisfiabilityDueToConflictingAxioms1(org.semanticweb.wolpertinger.WolpertingerTest)  Time elapsed: 0.072 sec  <<< ERROR!
java.lang.NullPointerException
	at org.semanticweb.wolpertinger.Wolpertinger.isConsistent(Wolpertinger.java:523)
	at org.semanticweb.wolpertinger.WolpertingerTest.testUnsatisfiabilityDueToConflictingAxioms1(WolpertingerTest.java:148)


Results :

Tests in error: 
  testDirectSubclass(org.semanticweb.wolpertinger.HierarchyTest)
  testIndirectSubclass(org.semanticweb.wolpertinger.HierarchyTest)
  testEquivalence(org.semanticweb.wolpertinger.HierarchyTest)
  testkSubsetOfB(org.semanticweb.wolpertinger.HierarchyTest)
  testFSubsetOfA(org.semanticweb.wolpertinger.HierarchyTest)
  testCSubsetOfE(org.semanticweb.wolpertinger.HierarchyTest)
  testThingSubsetOfNothing(org.semanticweb.wolpertinger.HierarchyTest)
  testNothingSubsetOfThing(org.semanticweb.wolpertinger.HierarchyTest)
  testUnsatisfiabilityDoToFixedDomain1(org.semanticweb.wolpertinger.WolpertingerTest)
  testSatisfiabilityOfSimpleGraphColring3Colors(org.semanticweb.wolpertinger.WolpertingerTest)
  testUnsatisfiabilityOfGraphColoringOverDomainOfSizeTwo(org.semanticweb.wolpertinger.WolpertingerTest)
  testSimple3ColoringHas24AnswerSets(org.semanticweb.wolpertinger.WolpertingerTest)
  testComplexConceptSubclassEntailment(org.semanticweb.wolpertinger.WolpertingerTest)
  testUnsatifiabilityDueToClashInABoxAssertions(org.semanticweb.wolpertinger.WolpertingerTest)
  testUnsatisfiabilityDuetoSimpleSubsumptionViolation(org.semanticweb.wolpertinger.WolpertingerTest)
  testUnsatisfiabilityDueToConflictingAxioms1(org.semanticweb.wolpertinger.WolpertingerTest)

Tests run: 16, Failures: 0, Errors: 16, Skipped: 0

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] Wolpertinger Reasoner 1.0.0-SNAPSHOT ............... SUCCESS [  0.652 s]
[INFO] Wolpertinger Reasoner Standalone 1.0 ............... FAILURE [ 20.898 s]
[INFO] Wolpertinger Reasoner Protege Plug-in 0.1.0-SNAPSHOT SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  33.312 s
[INFO] Finished at: 2023-06-28T11:08:41+02:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12.4:test (default-test) on project wolpertinger-reasoner: There are test failures.
[ERROR] 
[ERROR] Please refer to /home/ka/Downloads/Wolpertinger/wolpertinger-reasoner/target/surefire-reports for the individual test results.
[ERROR] -> [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/MojoFailureException
[ERROR] 
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR]   mvn <args> -rf :wolpertinger-reasoner

All 16 tests fail therefore the jar file and Protégé-Plugin aren't getting build. Can you provide a fix so I can generate them myself or upload the jar-file or Protégé here? That would be helpful!