NullPointerException in some case

[wallaroo]

io.camunda.zeebe.spring.client.bean.MethodInfo#getParameters and io.camunda.zeebe.spring.client.bean.MethodInfo#getParametersFilteredByAnnotation methods can throw a NullPointerException when org.springframework.core.LocalVariableTableParameterNameDiscoverer#getParameterNames(java.lang.reflect.Method) returns null

[berndruecker]

Hi @wallaroo - thanks for raising the issue. Do you know in which situations this can be null? Trying to understand the root cause.

[daniel-ewing]

Hi @berndruecker, as mentioned by @wallaroo, the fix in #462 doesn't actually address why L71 returns a null array. We have now had two support tickets for this issue. Is it possible that it is not thread safe to use LocalVariableTableParameterNameDiscoverer#getParameterNames as a static class and their needs to be a synchronized block around L71?

[harrybraun]

Hi @daniel-ewing, maybe one of the support tickets is from us. We are now experiencing the same problem in the cluster. Locally there is no problem, in the AWS EKS cluster we get an incident with the following error message every time a worker is started:

java.lang.NullPointerException: Cannot load from object array because "parameterNames" is null
  at io.camunda.zeebe.spring.client.bean.MethodInfo.getParameters(MethodInfo.java:75)
  at io.camunda.zeebe.spring.client.jobhandling.JobHandlerInvokingSpringBeans.handle(JobHandlerInvokingSpringBeans.java:46)
  at io.camunda.zeebe.client.impl.worker.JobRunnableFactory.executeJob(JobRunnableFactory.java:44)
  at io.camunda.zeebe.client.impl.worker.JobRunnableFactory.lambda$create$0(JobRunnableFactory.java:39)
  at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
  at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
  at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
  at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
  at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
  at java.base/java.lang.Thread.run(Thread.java:833)

We are currently using SpringBoot 3.1.4, locally OpenJDK 20, in the cluster probably Correto, Camunda 8.2.13 and Spring-Zeebe 8.2.4.

[akeller]

@1nb0und can you have a look? I know you mentioned digging into SpringBoot version compatibility today.

[sam0r040]

Hi, we also encountered this issue while trying to upgrade from Spring Boot 3.1.5 to 3.2.0 and therefore from spring-boot-starter-camunda from 8.3.1 to 8.3.4. We can reproduce this issue in our process tests and it is currently preventing us from updating to Spring Boot 3.2.0.

[1nb0und]

@sam0r040 Can you put some stacktrace that you were getting?

[sam0r040]

Sure:

io.camunda.zeebe.client.job.worker       : Worker JobWorker#handle failed to handle job with key 2251799813685282 of type ****, sending fail command to broker
java.lang.NullPointerException: Cannot load from object array because "parameterNames" is null
	at io.camunda.zeebe.spring.client.bean.MethodInfo.getParameters(MethodInfo.java:72) ~[spring-client-zeebe-8.3.4.1.jar:8.3.4.1]
	at io.camunda.zeebe.spring.client.jobhandling.JobHandlerInvokingSpringBeans.handle(JobHandlerInvokingSpringBeans.java:48) ~[spring-client-zeebe-8.3.4.1.jar:8.3.4.1]
	at io.camunda.zeebe.client.impl.worker.JobRunnableFactoryImpl.executeJob(JobRunnableFactoryImpl.java:45) ~[zeebe-client-java-8.3.4.jar:8.3.4]
	at io.camunda.zeebe.client.impl.worker.JobRunnableFactoryImpl.lambda$create$0(JobRunnableFactoryImpl.java:40) ~[zeebe-client-java-8.3.4.jar:8.3.4]
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) ~[na:na]
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na]
	at java.base/java.lang.Thread.run(Thread.java:840) ~[na:na]

[backslash47]

The error is happening because MethodInfo.getParameters.handle is depending on StandardReflectionParameterNameDiscoverer spring bean. And this bean requires the parameter names to be left alone during compilation.

Simple workaround is to use compileArgs -parameters for javac.

tasks.named('compileJava').configure {
    options.compilerArgs = ['-parameters']
}

[janmas]

@backslash47 is correct. The issue can be solved by specifying of javac option "-parameters". In IntelliJ it can be done by by Settings > Build, Execution, Deployment > Compiler > Java Compiler > Additional command line parameters (as mentioned in https://stackoverflow.com/questions/39217830/how-to-use-parameters-javac-option-in-intellij).

[1nb0und]

@wallaroo

1. Can you confirm if this solves your issue?
2. What Spring Boot version were you using?

It appears we encountered this issue when Spring Boot in this project was baselined to 3.2 and here are the PRs associated with it

#512

and the corresponding docs for the new flag has been added

Thank you @backslash47 and @janmas

[hzpz]

I can confirm that enabling method parameters metadata via the -java-parameters flag for the Kotlin compiler fixes the issue @sam0r040 described. Thanks!

[MMusaTR]

The error is happening because MethodInfo.getParameters.handle is depending on StandardReflectionParameterNameDiscoverer spring bean. And this bean requires the parameter names to be left alone during compilation.

Simple workaround is to use compileArgs -parameters for javac.

tasks.named('compileJava').configure {
    options.compilerArgs = ['-parameters']
}

where do we specify this in eclipse? anyone?

Thanks

[msjo66]

@MMusaTR
It can be put into pom.xml if using maven.
see https://maven.apache.org/plugins/maven-compiler-plugin/examples/pass-compiler-arguments.html

[MMusaTR]

@MMusaTR It can be put into pom.xml if using maven. see https://maven.apache.org/plugins/maven-compiler-plugin/examples/pass-compiler-arguments.html

I'm using gradle, I've specified following in build.gradle but still getting the NPE -
tasks.withType(JavaCompile) { options.compilerArgs << '-parameters' }

[msjo66]

@MMusaTR did you try following?

tasks.withType(JavaCompile) { options.compilerArgs.add("-parameters") }

[benno-huber]

I've also seen that NPE thrown in my Java client (spring-client-root v 8.4.0). It would be helpfull to detect faulty java class code ahead before it comes to NPE. That way some meanigfull error message could be thrown instead of NPE.

[jonathanlukas]

Fix provided in docs (add -parameters as compiler option) + error happens during init now