This website uses cookies. By clicking Accept, you consent to the use of cookies. Click Here to learn more about how we use cookies.
Accept
Reject
cancel
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for 
Search instead for 
Did you mean: 
Help

Head's Up! These forums are read-only. All users and content have migrated. Please join us at community.neo4j.com.

Null pointer Exception in Neo4J OGM

rajan1106
Node

‎11-15-2020 08:46 PM

I am intermittently getting an NPE when I execute a query under mild load.

java.lang.NullPointerException: null
 at org.neo4j.ogm.metadata.MetaData.classInfo(MetaData.java:123)
 at org.neo4j.ogm.context.GraphEntityMapper.executePostLoad(GraphEntityMapper.java:193)
 at org.neo4j.ogm.context.GraphEntityMapper.executePostLoad(GraphEntityMapper.java:180)
 at org.neo4j.ogm.context.GraphEntityMapper.map(GraphEntityMapper.java:120)
 at org.neo4j.ogm.context.GraphEntityMapper.map(GraphEntityMapper.java:83)
 at org.neo4j.ogm.context.RestModelMapper.map(RestModelMapper.java:84)
 at org.neo4j.ogm.session.delegates.ExecuteQueriesDelegate.lambda$query$0(ExecuteQueriesDelegate.java:137)
 at org.neo4j.ogm.session.Neo4jSession.doInTransaction(Neo4jSession.java:590)
 at org.neo4j.ogm.session.Neo4jSession.doInTransaction(Neo4jSession.java:564)
 at org.neo4j.ogm.session.delegates.ExecuteQueriesDelegate.query(ExecuteQueriesDelegate.java:134)
 at org.neo4j.ogm.session.Neo4jSession.query(Neo4jSession.java:435)

I have a Micronaut (Java) application that uses Neo4J-OGM, executes the query using Session on a database in Aura (cloud service).

Any idea why this call fail sometimes and work other times? Especially if there are no simultaneous calls.

0 Kudos
Reply
4 REPLIES 4

gerrit_meier
Neo4j
Neo4j

‎11-16-2020 11:05 PM

Could. you provide us more insights on your problem?
How does the domain object looks like, you are trying to get out of the call?
What query do you issue?

The message only tells me that Neo4j-OGM tries to find a class that is not registered in the mapping context.

0 Kudos
Reply

rajan1106
Node
In response to gerrit_meier

‎11-17-2020 02:11 PM

Yeah,
So I have (Portfolio)-[:HAS_ASSET]->(Asset)-[:HAS_BUILDING]->(Building)-[:HAS_ADDRESS]->(Address)

I am trying to get my building using UUID and populate Asset and Address of the building.

The query looks like this:

MATCH (b:Building) WHERE b.uuid = $buildingUuid WITH b RETURN b, [(b)-[r1:HAS_ADDRESS]-(addr:Address)|[r1, addr]], [(b)<-[r2:HAS_BUILDING]-(a:Asset)|[r2, a, [[(a)<-[r3:HAS_ASSET]-(p:Portfolio) | [r3, p]]]]] with params {buildingUuid=e1168f32-598a-40b4-b7f5-3be8b2a3c557}

It is a simple REST based application that works okay under low load. AS soon as I send multiple requests at the same time, some calls fail with the error above.

0 Kudos
Reply

aidan_fries
Node

‎01-31-2022 02:03 AM

Also experiencing the same (or similar issue).

I am getting an intermittent NPE being thrown when performing a simple read from the database.

It works sometimes and fails other times. I suspect it might be due to some conflict between loaded classes, but I have analysed the dependencies added in the application and cant see the problem.

The stacktrace I am seeing is:

java.lang.NullPointerException
        at org.neo4j.ogm.metadata.MetaData.classInfo(MetaData.java:113)
        at org.neo4j.ogm.context.SingleUseEntityMapper.writeProperty(SingleUseEntityMapper.java:162)
        at org.neo4j.ogm.context.SingleUseEntityMapper.setPropertiesOnEntity(SingleUseEntityMapper.java:111)
        at org.neo4j.ogm.context.SingleUseEntityMapper.map(SingleUseEntityMapper.java:104)
        at org.springframework.data.neo4j.repository.query.CustomResultConverter.convert(CustomResultConverter.java:62)
        at org.springframework.data.repository.query.ResultProcessor$ChainingConverter.convert(ResultProcessor.java:240)
        at org.springframework.data.repository.query.ResultProcessor$ChainingConverter.lambda$and$0(ResultProcessor.java:226)
        at org.springframework.data.repository.query.ResultProcessor$ChainingConverter.convert(ResultProcessor.java:240)
        at org.springframework.data.repository.query.ResultProcessor.processResult(ResultProcessor.java:170)
        at org.springframework.data.neo4j.repository.query.GraphRepositoryQuery.doExecute(GraphRepositoryQuery.java:79)
        at org.springframework.data.neo4j.repository.query.AbstractGraphRepositoryQuery.execute(AbstractGraphRepositoryQuery.java:57)
        at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:137)
        at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:121)
        at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:159)
        at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:138)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
        at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215)
        at com.sun.proxy.$Proxy182.findByUuid(Unknown Source)

I currently have the dependencies:

  • Spring Boot: 2.5.9 (hope to get to Spring Boot 2.6.3 when this issue is resolved)
  • Java 11 (hope to upgrade to Java 17 this year, but currently limited to Java 11)
  • neo4j-ogm-core: 3.2.28
  • neo4j-ogm-http-driver: 3.2.27
  • neo4j-java-driver: 4.4.0
0 Kudos
Reply

sameer_gijare14
Graph Buddy
In response to aidan_fries

‎02-04-2022 11:51 AM

Just check version compatibility of your installation. If everything compatible is installed then some classes are duplicates and placed in different jars but same package name/class path.So there could be some classes that are duplicates, located in different jars but java class loader is getting ambiguous and may be because of that it is giving null pointer error.
Many thanks
G Sam

0 Kudos
Reply
Nodes 2022
Nodes
NODES 2022, Neo4j Online Education Summit

All the sessions of the conference are now available online

Watch replays