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https://issues.apache.org/jira/browse/JENA-1260?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15670789#comment-15670789
]
ASF GitHub Bot commented on JENA-1260:
--------------------------------------
Github user afs commented on a diff in the pull request:
https://github.com/apache/jena/pull/193#discussion_r88263671
--- Diff:
jena-core/src/test/java/org/apache/jena/reasoner/test/TestRDFSReasoners.java ---
@@ -95,6 +95,7 @@ public static TestSuite suite() {
/**
* Build a single named query test
*/
+ @SuppressWarnings("unused")
private static void constructSingleQuerytests(TestSuite suite, String
manifest, String test, ReasonerFactory rf, Resource config) throws IOException {
--- End diff --
PRs are "live" - if the your branch changes so does the PR.
If you edit your branch and "push" it will change here as well.
To get rid of it, edit the file, then "git squash" or "git add" then "git
commit --amend" followed by "git push --force" and it will disappear from the
PR.
Or I can clean it after pulling it. This isn't a huge piece of work.
> NullPointerException when using an inferencing model under multithreaded load
> with query and delete
> ---------------------------------------------------------------------------------------------------
>
> Key: JENA-1260
> URL: https://issues.apache.org/jira/browse/JENA-1260
> Project: Apache Jena
> Issue Type: Bug
> Components: Jena
> Affects Versions: Jena 3.0.0
> Reporter: Stephen Owens
> Assignee: Dave Reynolds
> Attachments: TransitiveEngineFailureTest.java
>
>
> {noformat}
> java.lang.NullPointerException
> at java.util.HashSet.contains(HashSet.java:203)
> at
> org.apache.jena.reasoner.transitiveReasoner.TransitiveEngine.triage(TransitiveEngine.java:194)
> at
> org.apache.jena.reasoner.transitiveReasoner.TransitiveEngine.add(TransitiveEngine.java:234)
> at
> org.apache.jena.reasoner.rulesys.FBRuleInfGraph.prepare(FBRuleInfGraph.java:431)
> at
> org.apache.jena.reasoner.BaseInfGraph.requirePrepared(BaseInfGraph.java:530)
> at
> org.apache.jena.reasoner.rulesys.FBRuleInfGraph.findWithContinuation(FBRuleInfGraph.java:557)
> at
> org.apache.jena.reasoner.rulesys.FBRuleInfGraph.graphBaseFind(FBRuleInfGraph.java:587)
> at org.apache.jena.graph.impl.GraphBase.find(GraphBase.java:255)
> at
> org.apache.jena.sparql.engine.iterator.QueryIterTriplePattern$TripleMapper.<init>(QueryIterTriplePattern.java:75)
> at
> org.apache.jena.sparql.engine.iterator.QueryIterTriplePattern.nextStage(QueryIterTriplePattern.java:49)
> at
> org.apache.jena.sparql.engine.iterator.QueryIterRepeatApply.makeNextStage(QueryIterRepeatApply.java:108)
> at
> org.apache.jena.sparql.engine.iterator.QueryIterRepeatApply.hasNextBinding(QueryIterRepeatApply.java:65)
> at
> org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:111)
> at
> org.apache.jena.sparql.engine.iterator.QueryIterBlockTriples.hasNextBinding(QueryIterBlockTriples.java:63)
> at
> org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:111)
> at
> org.apache.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:39)
> at
> org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:111)
> at
> org.apache.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:39)
> at
> org.apache.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:111)
> at org.apache.jena.atlas.iterator.Iter$4.hasNext(Iter.java:264)
> at
> org.apache.jena.ext.com.google.common.collect.Iterators$5.hasNext(Iterators.java:547)
> at
> org.apache.jena.test.TransitiveEngineFailureTest$FailureTask.execQuery(TransitiveEngineFailureTest.java:109)
> at
> org.apache.jena.test.TransitiveEngineFailureTest$FailureTask.call(TransitiveEngineFailureTest.java:75)
> at
> org.apache.jena.test.TransitiveEngineFailureTest$FailureTask.call(TransitiveEngineFailureTest.java:1)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> This failure is due to the
> {{org.apache.jena.reasoner.transitiveReasoner.TransitiveEngine}} class
> declaring the {{subClassAliases}}
> member variable (of type HashSet<Node>) as static. The prepare method
> re-creates this shared variable whenever {{isPrepared}}
> is false:
> {noformat}
> private void prepare() {
> if (isPrepared) return;
> subClassAliases = new HashSet<>();
> . . .
> isPrepared = true;
> }
> {noformat}
> In particular, the static {{subClassAliases}} variable will be re-created
> whenever a {{TransitiveEngine}} object is created
> ({{isPrepared}} is false at creation time). Note that HashSet is neither
> thread-safe nor being accessed in a thread-safe manner.
> The combination of attempting to remove triples from the model and attempting
> to execute queries on the model leads
> to unsafe accesses to {{subClassAliases}}, which eventually leads to a null
> pointer exception.
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