Yes, you will want to exercise some control over concurrency here:
https://jena.apache.org/documentation/notes/concurrency-howto.html
---
A. Soroka
The University of Virginia Library
> On Apr 11, 2017, at 1:16 PM, Joshua TAYLOR <joshuaaa...@gmail.com> wrote:
>
> I expect the answer to my question is simply "make sure model access
> is synchronized", but just in case, I'm wondering whether this is
> expected behavior. Here's some code that modifies a model from a
> bunch of different threads. This doesn't cause an error every time,
> but occasionally throws, as shown in the stacktrace following the
> code.
>
> The class here is called OhDearTest, because I getting a
> `jena.shared.BrokenException oh dear, already have a slot for ...`
> earlier, which I'm still trying to reproduce. This code doesn't seem
> to trigger it. I've included a bit of that stacktrace at the very end.
>
> ## Code
>
> import org.apache.jena.rdf.model.Model;
> import org.apache.jena.rdf.model.ModelFactory;
> import org.apache.jena.rdf.model.Property;
> import org.apache.jena.rdf.model.Resource;
>
> public class OhDearTest {
> public static void main(String[] args) throws InterruptedException {
> int n = 1000;
> Model model = ModelFactory.createDefaultModel();
> Property p = model.createProperty("urn:ex:p");
> Thread[] thread = new Thread[n];
> for (int i = 0; i < n; i++) {
> thread[i] = new Thread(() -> {
> Resource r = model.createResource();
> r.addLiteral(p, "value");
> });
> thread[i].start();
> }
> for (int i = 0; i < n; i++) {
> thread[i].join();
> }
> }
> }
>
> ## Stacktrace
>
> Exception in thread "Thread-300" Exception in thread "Thread-299"
> Exception in thread "Thread-304" Exception in thread "Thread-282"
> Exception in thread "Thread-324" Exception in thread "Thread-331"
> Exception in thread "Thread-328"
> java.lang.ArrayIndexOutOfBoundsException: 905
> at org.apache.jena.mem.HashCommon.findSlot(HashCommon.java:164)
> at
> org.apache.jena.mem.HashedTripleBunch.contains(HashedTripleBunch.java:40)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:52)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:63)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
> java.lang.ArrayIndexOutOfBoundsException: 789
> at org.apache.jena.mem.HashCommon.findSlot(HashCommon.java:164)
> at
> org.apache.jena.mem.HashedTripleBunch.contains(HashedTripleBunch.java:40)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:52)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:63)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
> java.lang.ArrayIndexOutOfBoundsException: 827
> at org.apache.jena.mem.HashCommon.findSlot(HashCommon.java:164)
> at
> org.apache.jena.mem.HashedTripleBunch.contains(HashedTripleBunch.java:40)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:52)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:63)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
> java.lang.ArrayIndexOutOfBoundsException: 1061
> at org.apache.jena.mem.HashCommon.findSlot(HashCommon.java:164)
> at org.apache.jena.mem.HashedBunchMap.put(HashedBunchMap.java:66)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:51)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:60)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
> java.lang.ArrayIndexOutOfBoundsException: 918
> at org.apache.jena.mem.HashCommon.findSlot(HashCommon.java:164)
> at org.apache.jena.mem.HashedBunchMap.get(HashedBunchMap.java:59)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:50)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:60)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
> java.lang.ArrayIndexOutOfBoundsException: 1109
> at org.apache.jena.mem.HashCommon.findSlot(HashCommon.java:164)
> at org.apache.jena.mem.HashedBunchMap.get(HashedBunchMap.java:59)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:50)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:60)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
> java.lang.ArrayIndexOutOfBoundsException: 1144
> at org.apache.jena.mem.HashedBunchMap.put$(HashedBunchMap.java:87)
> at org.apache.jena.mem.HashedBunchMap.put(HashedBunchMap.java:70)
> at org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:51)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:60)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addLiteral(ResourceImpl.java:285)
> at OhDearTest.lambda$0(OhDearTest.java:15)
> at java.lang.Thread.run(Thread.java:745)
>
> ## The Oh Dear Exception
>
> The code above doesn't seem to produce this, but it's what I initially ran
> into.
>
> Caused by: org.apache.jena.shared.BrokenException: oh dear, already
> have a slot for 24e48338:15b5d4bfe76:-7ff3, viz 13
> at org.apache.jena.mem.HashedBunchMap.grow(HashedBunchMap.java:109)
> at org.apache.jena.mem.HashedBunchMap.put$(HashedBunchMap.java:90)
> at org.apache.jena.mem.HashedBunchMap.put(HashedBunchMap.java:70)
> at
> org.apache.jena.mem.NodeToTriplesMapMem.add(NodeToTriplesMapMem.java:51)
> at
> org.apache.jena.mem.GraphTripleStoreBase.add(GraphTripleStoreBase.java:60)
> at org.apache.jena.mem.GraphMem.performAdd(GraphMem.java:37)
> at org.apache.jena.graph.impl.GraphBase.add(GraphBase.java:181)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:1191)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:184)
> at org.apache.jena.rdf.model.impl.ModelCom.add(ModelCom.java:172)
> at
> org.apache.jena.rdf.model.impl.ResourceImpl.addProperty(ResourceImpl.java:263)
>
>
> --
> Joshua Taylor, http://www.cs.rpi.edu/~tayloj/
