Coherence Spring Data - When updating don't throw NullPointerException

[ghillert]

When doing an update for a non-existing id via CoherenceRepository using e.g.:

this.taskRepository.update(id, myModel -> {
        myModel.setDescription(description);
        return myModel;
    });

then a NullPointerException is thrown:

(Wrapped: Failed request execution for PartitionedCache service on Member(Id=1, Timestamp=2021-10-27 11:06:31.053, Address=10.10.0.15:62339, MachineId=14914, Location=process:61491, Role=IntellijRtJunitJUnitStarter)) java.lang.NullPointerException
	at com.tangosol.util.Base.ensureRuntimeException(Base.java:252)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.tagException(Grid.CDB:61)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache.onInvokeRequest(PartitionedCache.CDB:93)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$InvokeRequest.run(PartitionedCache.CDB:1)
	at com.tangosol.coherence.component.util.DaemonPool$WrapperTask.run(DaemonPool.CDB:1)
	at com.tangosol.coherence.component.util.DaemonPool$WrapperTask.run(DaemonPool.CDB:32)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.Service$DaemonPool$WrapperTask.run(Service.CDB:12)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.PartitionedService$DaemonPool$WrapperTask.run(PartitionedService.CDB:1)
	at com.tangosol.coherence.component.util.DaemonPool$Daemon.onNotify(DaemonPool.CDB:66)
	at com.tangosol.coherence.component.util.Daemon.run(Daemon.CDB:54)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:221)
	at com.oracle.coherence.examples.todo.server.service.SpringDataTaskService$lambda$update$c3e6a45f$1$0:CD693EBC65EA338BA81B91F7C8B386B4.lambda$update$c3e6a45f$1(Unknown Source)
	at com.oracle.coherence.examples.todo.server.service.SpringDataTaskService$lambda$update$c3e6a45f$1$0:CD693EBC65EA338BA81B91F7C8B386B4.apply(Unknown Source)
	at com.oracle.coherence.repository.AbstractRepositoryBase$lambda$updateFunctionProcessor$b845d0ab$1$0:8240A1DA38A2C604E65046FD1F877E5F.lambda$updateFunctionProcessor$b845d0ab$1(Unknown Source)
	at com.oracle.coherence.repository.AbstractRepositoryBase$lambda$updateFunctionProcessor$b845d0ab$1$0:8240A1DA38A2C604E65046FD1F877E5F.process(Unknown Source)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$Storage.invoke(PartitionedCache.CDB:17)
	at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache.onInvokeRequest(PartitionedCache.CDB:56)
	... 8 more

We should throw a more business-friendly exception, possibly even considering returning Spring data exceptions:

See: https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/dao/package-summary.html

[aseovic]

Yeah, the exception is not the friendliest, because it has occurred during remote lambda invocation, but it is the correct one.

There are no guarantees that the value is not going to be null, so the code should check for that (and typically create a new instance to update):

this.taskRepository.update(id, myModel -> {
        if (myModel == null) {
            myModel = new MyModel(id);
        }
        myModel.setDescription(description);
        return myModel;
    });

Which can also be done using one of the update method overloads, which allow you to specify a value supplier that should be used to create a new value instance when the existing value is null:

this.taskRepository.update(id, MyModel::setDescription, description, MyModel::new);

[ghillert]

@aseovic Just revisiting this a bit more. The relevant code is in AbstractRepositoryBase in Coherence package com.oracle.coherence.repository:

            if (entity == null && factory != null)
                {
                entity = factory.create(entry.getKey());
                }
            updater.update(entity, value);

I would think that if the entity is null and the factory is null, an IllegalStateException should be throw, without calling the updater with a null argument causing the nullpointerexception.

[ghillert]

Added some documentation explain the situation plus work-around.