Unable to start component "CELOE" when using SPARQL endpoint and SPARQL reasoner

[Jean-KOUAGOU]

I am using a public SPARQL endpoint as knowledge source for DL-Learner but I cannot get it running. Is there any workaround? More details on the errors below

java.lang.RuntimeException: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'alg': Initialization of bean failed; nested exception is java.lang.RuntimeException: java.lang.RuntimeException: Error sending query "PREFIX owl:<http://www.w3.org/2002/07/owl#> PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> SELECT ?var1 WHERE {?var1 a owl:Class .}" to endpoint https://dbpedia.data.dice-research.org/sparql
	at org.dllearner.configuration.spring.DefaultApplicationContextBuilder.buildApplicationContext(DefaultApplicationContextBuilder.java:62)
	at org.dllearner.cli.CLI.main(CLI.java:213)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'alg': Initialization of bean failed; nested exception is java.lang.RuntimeException: java.lang.RuntimeException: Error sending query "PREFIX owl:<http://www.w3.org/2002/07/owl#> PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> SELECT ?var1 WHERE {?var1 a owl:Class .}" to endpoint https://dbpedia.data.dice-research.org/sparql
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:481)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:756)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
	at org.dllearner.configuration.spring.DefaultApplicationContextBuilder.buildApplicationContext(DefaultApplicationContextBuilder.java:60)
	... 1 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: Error sending query "PREFIX owl:<http://www.w3.org/2002/07/owl#> PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> SELECT ?var1 WHERE {?var1 a owl:Class .}" to endpoint https://dbpedia.data.dice-research.org/sparql
	at org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor.postProcessBeforeInitialization(ComponentInitializationBeanPostProcessor.java:46)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:407)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1611)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
	... 10 more
Caused by: java.lang.RuntimeException: Error sending query "PREFIX owl:<http://www.w3.org/2002/07/owl#> PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> SELECT ?var1 WHERE {?var1 a owl:Class .}" to endpoint https://dbpedia.data.dice-research.org/sparql
	at org.dllearner.reasoning.SPARQLReasoner.executeSelectQuery(SPARQLReasoner.java:2633)
	at org.dllearner.reasoning.SPARQLReasoner.executeSelectQuery(SPARQLReasoner.java:2638)
	at org.dllearner.reasoning.SPARQLReasoner.getOWLClasses(SPARQLReasoner.java:1100)
	at org.dllearner.reasoning.SPARQLReasoner.getOWLClasses(SPARQLReasoner.java:1091)
	at org.dllearner.reasoning.SPARQLReasoner.getClasses(SPARQLReasoner.java:1087)
	at org.dllearner.reasoning.SPARQLReasoner.getClasses(SPARQLReasoner.java:96)
	at org.dllearner.utilities.Helper.computeConcepts(Helper.java:154)
	at org.dllearner.core.AbstractCELA.initClassHierarchy(AbstractCELA.java:407)
	at org.dllearner.algorithms.celoe.CELOE.init(CELOE.java:253)
	at org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor.postProcessBeforeInitialization(ComponentInitializationBeanPostProcessor.java:35)
	... 13 more
Caused by: java.lang.UnsupportedOperationException: Not Implemented.
	at org.aksw.jena_sparql_api.utils.query_execution.QueryExecutionAdapter.setTimeout(QueryExecutionAdapter.java:101)
	at org.dllearner.reasoning.SPARQLReasoner.executeSelectQuery(SPARQLReasoner.java:2627)
	... 22 more

[Jean-KOUAGOU]

An overview of all steps that have passed before the error occured:

0    [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Initializing component 'op' of type Refinement Operator TDT ...
2    [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - ... initialized component 'op' in 0ms. Status: OK
41   [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Initializing component 'ks' of type SPARQL endpoint ...
553  [main] INFO  org.dllearner.kb.SparqlEndpointKS  - SPARQL KB setup:
Endpoint:       Remote                   
URL:            https://dbpedia.data.dice-research.org/sparql
Cache:          /tmp/sparql-cache;COMPRESS=TRUE
Delay:          50ms

553  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - ... initialized component 'ks' in 512ms. Status: OK
556  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Initializing component 'reasoner' of type SPARQL Reasoner ...
556  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - ... initialized component 'reasoner' in 0ms. Status: OK
560  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Initializing component 'accuracyMethod' of type FMeasure ...
560  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - ... initialized component 'accuracyMethod' in 0ms. Status: OK
564  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Initializing component 'lp' of type PosNegLPStandard ...
565  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - ... initialized component 'lp' in 1ms. Status: OK
581  [main] INFO  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Initializing component 'alg' of type CELOE ...
581  [main] WARN  org.dllearner.core.AbstractCELA  - Ignoring unsatisfiable check due to org.dllearner.reasoning.SPARQLReasoner.getInconsistentClassesImpl(SPARQLReasoner.java:1863)
595  [main] WARN  org.dllearner.configuration.spring.ComponentInitializationBeanPostProcessor  - Could not initialize component "CELOE"
599  [main] ERROR org.dllearner.cli.CLI  - An Error Has Occurred During Processing.
600  [main] ERROR org.dllearner.cli.CLI  - Not Implemented.
600  [main] ERROR org.dllearner.cli.CLI  - Terminating DL-Learner...and writing stacktrace to: log/error.log

[SimonBin]

duplicate of #111

you can use version 1.4.0 if you need remote sparql endpoint

[Jean-KOUAGOU]

Thanks for your reply. I have downloaded version 1.4.0. I do not get the error above, but the execution stops after displying start class 'T' and without any error. Also, the produced searchTree file is empty, see the actual output below:

DL-Learner command line interface
Initializing component 'op' of type Refinement Operator TDT ...
... initialized component 'op' in 0ms. Status: OK
Initializing component 'ks' of type SPARQL endpoint ...
SPARQL KB setup:
Endpoint:       Remote                   
URL:            https://dbpedia.data.dice-research.org/sparql
Cache:          /tmp/sparql-cache;COMPRESS=TRUE
Delay:          50ms

... initialized component 'ks' in 471ms. Status: OK
Initializing component 'reasoner' of type SPARQL Reasoner ...
... initialized component 'reasoner' in 0ms. Status: OK
Initializing component 'accuracyMethod' of type FMeasure ...
... initialized component 'accuracyMethod' in 0ms. Status: OK
Initializing component 'lp' of type PosNegLPStandard ...
... initialized component 'lp' in 0ms. Status: OK
Initializing component 'alg' of type CELOE ...
Ignoring unsatisfiable check due to org.dllearner.reasoning.SPARQLReasoner.getInconsistentClassesImpl(SPARQLReasoner.java:1601)
Preparing object property subsumption hierarchy ...
... done in 106ms
Preparing data property subsumption hierarchy ...
... done in 106ms
Numeric Facet restrictions are not (yet) implemented for SPARQL Reasoner, option ignored
Time based Facet restrictions are not (yet) implemented for SPARQL Reasoner, option ignored
Cardinality restrictions in Sparql not fully implemented, defaulting to 10.
... initialized component 'alg' in 983ms. Status: OK
Running algorithm instance "alg" (CELOE)
start class:⊤

How can I get the algorithm to execute properly? For now I have set the max_runtime to 1000, but the execution lasts at most 60 seconds

[Jean-KOUAGOU]

I am executing the algorithm a large dataset, DBpedia with over 800 million statements. Should Java memory size be increased?