[jira] [Created] (VELOCITY-934) NullPointerException under high concurrency

["Andreas Hager (Jira)" <ji...@apache.org>]

Andreas Hager created VELOCITY-934:
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             Summary: NullPointerException under high concurrency
                 Key: VELOCITY-934
                 URL: https://issues.apache.org/jira/browse/VELOCITY-934
             Project: Velocity
          Issue Type: Bug
          Components: Engine
    Affects Versions: 2.2, 1.7.x
         Environment: Windows 10 Professional

            Reporter: Andreas Hager


I adjusted the mboseke/template-benchmark to profile throughput on AMD Ryzen 5950x:

[https://github.com/casid/template-benchmark/tree/ryzen-5950x]

With 32 concurrent threads, I can reliably reproduce a runtime exception in the Apache Velocity benchmark:
{code:java}
java.lang.NullPointerException
        at org.apache.velocity.runtime.directive.Directive.postRender(Directive.java:240)
        at org.apache.velocity.runtime.directive.Foreach.clean(Foreach.java:325)
        at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:292)
        at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:301)
        at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:423)
        at org.apache.velocity.Template.merge(Template.java:358)
        at org.apache.velocity.Template.merge(Template.java:262)
        at com.mitchellbosecke.benchmark.Velocity.benchmark(Velocity.java:34)
        at com.mitchellbosecke.benchmark.generated.Velocity_benchmark_jmhTest.benchmark_thrpt_jmhStub(Velocity_benchmark_jmhTest.java:122)
        at com.mitchellbosecke.benchmark.generated.Velocity_benchmark_jmhTest.benchmark_Throughput(Velocity_benchmark_jmhTest.java:69)
        at jdk.internal.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:430)
        at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:412)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)

{code}
This initially happened with version 1.7, but after updating to 2.2 the problem is still there. It looks like there is some threading issue under high concurrency.

This is the velocity benchmark class:

[https://github.com/casid/template-benchmark/blob/ryzen-5950x/src/main/java/com/mitchellbosecke/benchmark/Velocity.java]

And this is the velocity template:

[https://github.com/casid/template-benchmark/blob/ryzen-5950x/src/main/resources/templates/stocks.velocity.html]

 

 

 

 



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