[jira] [Commented] (BEAM-12215) DirectRunner NullPointerException

["Beam JIRA Bot (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BEAM-12215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17375877#comment-17375877 ] 

Beam JIRA Bot commented on BEAM-12215:
--------------------------------------

This issue was marked "stale-P2" and has not received a public comment in 14 days. It is now automatically moved to P3. If you are still affected by it, you can comment and move it back to P2.

> DirectRunner NullPointerException
> ---------------------------------
>
>                 Key: BEAM-12215
>                 URL: https://issues.apache.org/jira/browse/BEAM-12215
>             Project: Beam
>          Issue Type: Bug
>          Components: runner-direct, sdk-java-core, testing
>    Affects Versions: 2.28.0
>            Reporter: Lai Jiang
>            Priority: P3
>
> When using the {{DirectRunner}} in tests I encountered flaky tests due to {{NullPointerException}}.
> When the test fails the relevant stack trace is like below:
>  
>  
> {code:java}
> java.lang.NullPointerException
>  at org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkNotNull(Preconditions.java:877)
>  at org.apache.beam.vendor.guava.v26_0_jre.com.google.common.util.concurrent.ThreadFactoryBuilder.setThreadFactory(ThreadFactoryBuilder.java:132)
>  at org.apache.beam.runners.direct.DirectRunner.run(DirectRunner.java:192)
>  at org.apache.beam.runners.direct.DirectRunner.run(DirectRunner.java:67)
>  at org.apache.beam.sdk.Pipeline.run(Pipeline.java:322)
>  at google.registry.beam.TestPipelineExtension.run(TestPipelineExtension.java:344)
>  at google.registry.beam.TestPipelineExtension.run(TestPipelineExtension.java:324)
>  at google.registry.beam.spec11.Spec11PipelineTest.testSuccess_saveToGcs(Spec11PipelineTest.java:185){code}
>  
>  
> However the null pointer seems to have come from calling (a repackaged and very innocent looking) guava function to set the {{ThreadFactory}}:
>  
> {code:java}
>  ExecutorService metricsPool =
>  Executors.newCachedThreadPool(
>  new ThreadFactoryBuilder()
> .setThreadFactory(MoreExecutors.platformThreadFactory())
>  .setDaemon(false) // otherwise you say you want to leak, please don't!
>  .setNameFormat("direct-metrics-counter-committer")
>  .build());{code}
>  
> Which in turn is just calling java.util.concurrent.Executors.defaulThreatFactory() when not on App Engine:
>  
> {code:java}
> @Beta
> @GwtIncompatible
> public static ThreadFactory platformThreadFactory() {
>  if (!isAppEngine()) {
>   return Executors.defaultThreadFactory();
>   } else {
>  ...
> } {code}
>  
> I don't understand how this could possibly have failed. The test seems to be only flaky on our CI servers running Ubuntu and I haven't been able to reproduce it locally, making debugging a challenge.
>  
> I'd appreciate any input you may have. Thanks!



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