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[Bug]: NullPointerException from ResourceReaper in GenericContainer.stop #11492
Description
Module
Core
Testcontainers version
2.0.3
Using the latest Testcontainers version?
Yes
Host OS
Linux
Host Arch
x86
Docker version
GitHub hosted runnersWhat happened?
java.lang.NullPointerException: Cannot invoke "Object.hashCode()" because "key" is null
at java.base/java.util.concurrent.ConcurrentHashMap.replaceNode(ConcurrentHashMap.java:1125)
at java.base/java.util.concurrent.ConcurrentHashMap.remove(ConcurrentHashMap.java:1116)
at org.testcontainers.utility.ResourceReaper.stopAndRemoveContainer(ResourceReaper.java:175)
at org.testcontainers.containers.GenericContainer.stop(GenericContainer.java:652)
at io.trino.tests.product.launcher.env.DockerContainer.reset(DockerContainer.java:411)
at io.trino.tests.product.launcher.env.Environment.tryStart(Environment.java:157)
Exact repro steps are unclear.
Based on exceptions logged earlier in the CI run (https://github.com/trinodb/trino/actions/runs/22016571723/job/63619535768?pr=28120) this may be after a failed startup attempt.
Relevant log output
Additional Information
https://github.com/trinodb/trino/actions/runs/22016571723/job/63619535768?pr=28120
Activity
PreAgile commentedon Mar 27, 2026
I took a look at this — the NPE comes from
ConcurrentHashMap.remove(null)insidestopAndRemoveContainer(), sinceConcurrentHashMapdoesn't accept null keys.One thing I noticed is that
GenericContainer.stop()already guards against a nullcontainerIdbefore calling intoResourceReaper, so it's not obvious how null gets through. Could be a race or another caller hitting the deprecated overload.I'm thinking a simple null check (early return) in both
stopAndRemoveContainer()overloads would prevent the crash. The deeper root cause could be investigated separately if needed.Would that approach work, or would you prefer finding the exact path first?
radhika4229 commentedon Aug 3, 2026
"Hi, I'd like to work on this if it's still open. Could you share any pointers on reproducing this or which part of ResourceReaper is involved?"