You have the wrong execution-engine, you need the javacompat one. Your results contain nodes to access them (for printing) you need a transaction. There is a result.dumpToString() method which you can use within your transaction.
Or just return attributes of the nodes from your query. Michael Am 04.09.2014 um 21:37 schrieb [email protected]: > Hi Sukaant, > > I tried integrating my database with Java. I created a small java > application, added neo4j dependency in pom.xml. > > Below is the code I wrote. > > GraphDatabaseService db = new > GraphDatabaseFactory().newEmbeddedDatabase("path of my db"); > ExecutionEngine engine = new ExecutionEngine(db, > StringLogger.SYSTEM ); > > ExecutionResult result; > try ( Transaction ignored = db.beginTx() ) > { > result = engine.execute( "match (n) return n" ); > } > > System.out.print(result); > db.shutdown(); > > This is throwing the below error. I tried looking for the solution, but that > was not successful. Below is the error i received. > > Exception in thread "main" org.neo4j.graphdb.TransactionFailureException: > Failed to mark transaction as rollback only. > at > org.neo4j.kernel.TopLevelTransaction.markAsRollbackOnly(TopLevelTransaction.java:97) > at > org.neo4j.kernel.TopLevelTransaction.failure(TopLevelTransaction.java:86) > at > org.neo4j.cypher.internal.spi.v2_1.TransactionBoundQueryContext.close(TransactionBoundQueryContext.scala:65) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.DelegatingQueryContext.close(DelegatingQueryContext.scala:38) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext.org$neo4j$cypher$internal$compiler$v2_1$spi$ExceptionTranslatingQueryContext$$super$close(ExceptionTranslatingQueryContext.scala:34) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext$$anonfun$close$1.apply$mcV$sp(ExceptionTranslatingQueryContext.scala:34) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext$$anonfun$close$1.apply(ExceptionTranslatingQueryContext.scala:34) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext$$anonfun$close$1.apply(ExceptionTranslatingQueryContext.scala:34) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext.org$neo4j$cypher$internal$compiler$v2_1$spi$ExceptionTranslatingQueryContext$$translateException(ExceptionTranslatingQueryContext.scala:152) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext.close(ExceptionTranslatingQueryContext.scala:34) > at > org.neo4j.cypher.internal.compiler.v2_1.spi.DelegatingQueryContext.close(DelegatingQueryContext.scala:38) > at > org.neo4j.cypher.internal.compiler.v2_1.executionplan.ExecutionWorkflowBuilder$$anonfun$runWithQueryState$1.apply(ExecutionPlanBuilder.scala:164) > at > org.neo4j.cypher.internal.compiler.v2_1.executionplan.ExecutionWorkflowBuilder$$anonfun$runWithQueryState$1.apply(ExecutionPlanBuilder.scala:164) > at > org.neo4j.cypher.internal.compiler.v2_1.TaskCloser$$anonfun$1.apply(TaskCloser.scala:43) > at > org.neo4j.cypher.internal.compiler.v2_1.TaskCloser$$anonfun$1.apply(TaskCloser.scala:41) > at > scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251) > at > scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251) > at scala.collection.immutable.List.foreach(List.scala:318) > at > scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:251) > at scala.collection.AbstractTraversable.flatMap(Traversable.scala:105) > at > org.neo4j.cypher.internal.compiler.v2_1.TaskCloser.close(TaskCloser.scala:40) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator$$anonfun$close$1.apply$mcV$sp(ClosingIterator.scala:67) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator$$anonfun$close$1.apply(ClosingIterator.scala:67) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator$$anonfun$close$1.apply(ClosingIterator.scala:67) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator$$anonfun$translateException$1.apply(ClosingIterator.scala:72) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator.decoratedCypherException(ClosingIterator.scala:102) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator.translateException(ClosingIterator.scala:70) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator.close(ClosingIterator.scala:66) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator$$anonfun$failIfThrows$1.apply(ClosingIterator.scala:96) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator.decoratedCypherException(ClosingIterator.scala:102) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator.failIfThrows(ClosingIterator.scala:91) > at > org.neo4j.cypher.internal.compiler.v2_1.ClosingIterator.hasNext(ClosingIterator.scala:34) > at > org.neo4j.cypher.internal.compiler.v2_1.PipeExecutionResult.hasNext(PipeExecutionResult.scala:167) > at scala.collection.Iterator$class.toString(Iterator.scala:1153) > at > org.neo4j.cypher.internal.compiler.v2_1.PipeExecutionResult.toString(PipeExecutionResult.scala:35) > at java.lang.String.valueOf(String.java:2854) > at java.io.PrintStream.print(PrintStream.java:683) > at cricketFun.main(cricketFun.java:25) > Caused by: java.lang.NullPointerException > at > org.neo4j.kernel.TopLevelTransaction.markAsRollbackOnly(TopLevelTransaction.java:93) > ... 37 more > > > Why is it failing to fetch the data? Am I doing anything wrong? Also, if I > tried running the application second time, it throws me this error. > > > Exception in thread "main" java.lang.RuntimeException: Error starting > org.neo4j.kernel.EmbeddedGraphDatabase, > C:\Users\sd482\Documents\Neo4j\default.graphdb > at > org.neo4j.kernel.InternalAbstractGraphDatabase.run(InternalAbstractGraphDatabase.java:362) > at > org.neo4j.kernel.EmbeddedGraphDatabase.<init>(EmbeddedGraphDatabase.java:59) > at > org.neo4j.graphdb.factory.GraphDatabaseFactory$1.newDatabase(GraphDatabaseFactory.java:90) > at > org.neo4j.graphdb.factory.GraphDatabaseBuilder.newGraphDatabase(GraphDatabaseBuilder.java:199) > at > org.neo4j.graphdb.factory.GraphDatabaseFactory.newEmbeddedDatabase(GraphDatabaseFactory.java:70) > at cricketFun.main(cricketFun.java:16) > Caused by: org.neo4j.kernel.lifecycle.LifecycleException: Component > 'org.neo4j.kernel.StoreLockerLifecycleAdapter@f1bb79c' was successfully > initialized, but failed to start. Please see attached cause exception. > at > org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:513) > at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:115) > at > org.neo4j.kernel.InternalAbstractGraphDatabase.run(InternalAbstractGraphDatabase.java:339) > ... 5 more > Caused by: org.neo4j.kernel.StoreLockException: Unable to obtain lock on > store lock file: C:\Users\sd482\Documents\Neo4j\default.graphdb\store_lock. > Please ensure no other process is using this database, and that the directory > is writable (required even for read-only access) > at org.neo4j.kernel.StoreLocker.checkLock(StoreLocker.java:82) > at > org.neo4j.kernel.StoreLockerLifecycleAdapter.start(StoreLockerLifecycleAdapter.java:44) > at > org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:507) > ... 7 more > Caused by: java.io.IOException: Couldn't lock lock file > C:\Users\sd482\Documents\Neo4j\default.graphdb\lock because another process > already holds the lock. > at > org.neo4j.kernel.impl.nioneo.store.FileLock.getLockFileBasedFileLock(FileLock.java:120) > at > org.neo4j.kernel.impl.nioneo.store.FileLock.getOsSpecificFileLock(FileLock.java:64) > at > org.neo4j.kernel.DefaultFileSystemAbstraction.tryLock(DefaultFileSystemAbstraction.java:93) > at org.neo4j.kernel.StoreLocker.checkLock(StoreLocker.java:74) > ... 9 more > > > I know this is due to the locking issue. Though I'm using "db.shutdown();" in > my code, it is not unlocking the database when the application is terminated. > I had to close the IDE everytime to unlock it. Please let me know where I am > making the mistake. > > Sorry for the very long question, and thank you so much for your help. :) > > Thanks, > Shashank > > > > On Thursday, September 4, 2014 5:17:22 AM UTC-4, Sukaant Chaudhary wrote: > Hi Shashank, > Use the code in the following link, it is cypher-jdbc, it will help you to > integrate with Java: > http://docs.neo4j.org/chunked/stable/tutorials-cypher-java.html > > You need the following dependency: > <dependency> > <groupId>org.neo4j</groupId> > <artifactId>neo4j-kernel</artifactId> > <version>${neo4j.version}</version> > </dependency> > > About Tomcat and Maven > Tomcat is a Server whereas Maven is a build tool both are different things. > > Hope this will help. > If you have any further queries please feel free to ask. > > -Sukaant Chaudhary > > > > On Thu, Sep 4, 2014 at 7:22 AM, <[email protected]> wrote: > Hello, > > My name is Shashank. I am currently a Masters student. I am trying to explore > new technologies and new to Neo4j. I have basic idea on nodes, relationships > and querying the database. I have developed a small database in my laptop. I > want to integrate it with Java and implement few algorithms on the data (like > apriori algorithm) for my data mining project. > > Is it a good idea to use Neo4j for data mining. If so, please let me know any > example that can fetch data from Neo4j server using Java. Also, I was > wondering whether we can use Tomcat instead of Maven. > > Your help is very much appreciated. > > Thanks, > Shashank > > -- > You received this message because you are subscribed to the Google Groups > "Neo4j" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "Neo4j" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
