log4j spring boot 4 autoinstrumentation by lbloder · Pull Request #5403 · getsentry/sentry-java

lbloder · 2026-05-11T15:21:54Z

📜 Description

💡 Motivation and Context

resolves: #5035

💚 How did you test it?

📝 Checklist

I added GH Issue ID & Linear ID
I added tests to verify the changes.
No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
I updated the docs if needed.
I updated the wizard if needed.
Review from the native team if needed.
No breaking change or entry added to the changelog.
No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

sentry · 2026-05-11T15:24:09Z

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.49.0 (1)	release

⚙️ sentry-android Build Distribution Settings

github-actions · 2026-05-11T15:31:44Z

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	319.10 ms	377.16 ms	58.06 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`eb95ded`	317.51 ms	369.08 ms	51.57 ms
`2124a46`	319.19 ms	415.04 ms	95.85 ms
`c3ee041`	310.64 ms	361.90 ms	51.26 ms
`dcc6bbf`	382.58 ms	462.13 ms	79.54 ms
`7a19fee`	315.46 ms	368.62 ms	53.16 ms
`9054d65`	330.94 ms	403.24 ms	72.30 ms
`d500866`	326.13 ms	378.70 ms	52.58 ms
`ad8da22`	365.86 ms	427.00 ms	61.14 ms
`ed33deb`	337.52 ms	484.06 ms	146.54 ms
`d15471f`	310.26 ms	377.04 ms	66.78 ms

App size

Revision	Plain	With Sentry	Diff
`eb95ded`	0 B	0 B	0 B
`2124a46`	1.58 MiB	2.12 MiB	551.51 KiB
`c3ee041`	0 B	0 B	0 B
`dcc6bbf`	1.58 MiB	2.12 MiB	553.10 KiB
`7a19fee`	0 B	0 B	0 B
`9054d65`	1.58 MiB	2.29 MiB	723.38 KiB
`d500866`	0 B	0 B	0 B
`ad8da22`	1.58 MiB	2.29 MiB	719.83 KiB
`ed33deb`	1.58 MiB	2.13 MiB	559.52 KiB
`d15471f`	1.58 MiB	2.13 MiB	559.54 KiB

Previous results on branch: feat/log4j-autoinstrumentation

Startup times

Revision	Plain	With Sentry	Diff
`c488aa4`	392.38 ms	468.44 ms	76.06 ms
`e13dc15`	377.54 ms	433.90 ms	56.36 ms
`6f3172f`	504.00 ms	585.84 ms	81.84 ms

App size

Revision	Plain	With Sentry	Diff
`c488aa4`	0 B	0 B	0 B
`e13dc15`	0 B	0 B	0 B
`6f3172f`	0 B	0 B	0 B

… loggers to attach to

lbloder · 2026-05-12T13:45:31Z

@sentry review

lbloder · 2026-05-12T13:47:59Z

cursor review

cursor

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 7d76aa5. Configure here.}

lbloder · 2026-07-14T11:14:58Z

@adinauer should we add a separate spring-boot-log4j sample for e2e tets?

adinauer

Mostly LGTM, just needs to be opt-in for now, to not break manual setups on upgrade. Separate sample + E2E tests sounds good

Co-authored-by: Alexander Dinauer <adinauer@users.noreply.github.com>

cursor · 2026-07-21T12:27:04Z

+  private boolean isSentryAppenderRegistered(final @NotNull LoggerConfig loggerConfig) {
+    return loggerConfig.getAppenders().values().stream()
+        .anyMatch(appender -> appender.getClass().equals(SentryAppender.class));
+  }


Incomplete existing appender check

Medium Severity

isSentryAppenderRegistered only looks at the target logger and requires an exact SentryAppender class match. A manually configured appender on another logger, or a subclass, does not block auto-registration, so a second appender can still be added. That conflicts with the changelog claim that existing manual SentryAppender setup takes precedence.

Additional Locations (1)

CHANGELOG.md#L56-L57

^{Reviewed by Cursor Bugbot for commit 53f53f6. Configure here.}

…move log4j dependencies in spring-boot-4 sample

sentry · 2026-07-22T06:06:53Z

+    ISpan currentSpan = Sentry.getSpan();
+    ISpan sentrySpan = currentSpan.startChild("spanCreatedThroughSentryApi");
+    try {


Bug: The result of Sentry.getSpan() is used without a null check. This can cause a NullPointerException as the method is annotated with @Nullable.
_{Severity: MEDIUM}

Suggested Fix

Add a null check after calling Sentry.getSpan() and before calling .startChild() on the result. Only proceed to create a child span if the currentSpan is not null. For example: if (currentSpan != null) { ISpan sentrySpan = currentSpan.startChild("..."); }.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not valid. Location: sentry-samples/sentry-samples-spring-boot-4-log4j2/src/main/java/io/sentry/samples/spring/boot4/PersonController.java#L27-L29 Potential issue: The `Sentry.getSpan()` method is annotated with `@Nullable`, indicating it can return `null`. However, the code in `PersonController.java` directly calls `.startChild()` on the returned `ISpan` object without a null check. This will cause a `NullPointerException` if no active Sentry transaction is present. This can occur under realistic conditions, such as when tracing is disabled (e.g., `sentry.traces-sample-rate=0`), the Sentry DSN is missing, or if the `SentryTracingFilter` fails to initialize.

Also affects:

sentry-samples/sentry-samples-spring-boot-4-log4j2/src/main/java/io/sentry/samples/spring/boot4/PersonController.java:47~48

_{Did we get this right? 👍 / 👎 to inform future reviews.}

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 4362c07. Configure here.}

cursor · 2026-07-22T06:07:48Z

+
+    final LoggerConfig newLoggerConfig = new LoggerConfig(loggerName, null, true);
+    newLoggerConfig.setParent(loggerConfig);
+    configuration.addLogger(loggerName, newLoggerConfig);


Duplicate events with nested loggers

Medium Severity

Newly created logger configs always use additive=true. When both ROOT and a child logger are listed—as in the changelog example—and the child config does not already exist, the same log event is delivered to SentryAppender on the child and again on ROOT via additivity, producing duplicate events, breadcrumbs, and structured logs.

Additional Locations (1)

CHANGELOG.md#L35-L40

^{Reviewed by Cursor Bugbot for commit 4362c07. Configure here.}

lbloder · 2026-07-24T07:24:40Z

@adinauer added the sample and e2e tests

lbloder added 3 commits May 11, 2026 17:17

initial log4j appender auto config

4e03272

Improve Log4j2 appender auto-configuration tests

4536c32

Merge branch 'main' into feat/log4j-autoinstrumentation

a3d7b83

lbloder added 2 commits May 12, 2026 14:39

remove ancestor safeguard to match logback, as the user defines which…

d896d43

… loggers to attach to

add changelog

7d76aa5

cursor Bot reviewed May 12, 2026

View reviewed changes

lbloder marked this pull request as ready for review May 26, 2026 06:35

lbloder requested review from 0xadam-brown, adinauer, markushi, romtsn and runningcode as code owners May 26, 2026 06:35

Merge branch 'main' into feat/log4j-autoinstrumentation

2493682

cursor Bot reviewed Jul 14, 2026

View reviewed changes

Comment thread sentry-samples/sentry-samples-spring-boot-4/build.gradle.kts Outdated

move changelog entry to unrelease section

70939c1

adinauer reviewed Jul 21, 2026

View reviewed changes

Comment thread sentry-spring-boot-4/src/main/java/io/sentry/spring/boot4/SentryLog4j2Initializer.java

Comment thread CHANGELOG.md Outdated

Update CHANGELOG.md

53f53f6

Co-authored-by: Alexander Dinauer <adinauer@users.noreply.github.com>

cursor Bot reviewed Jul 21, 2026

View reviewed changes

add log4j sample and system tests, log4j autoconfig is now opt-in, re…

49be228

…move log4j dependencies in spring-boot-4 sample

cursor Bot reviewed Jul 21, 2026

View reviewed changes

Comment thread ...g-boot-4/src/test/kotlin/io/sentry/spring/boot4/SentryLog4j2AppenderAutoConfigurationTest.kt

add test for logging enabled/disabled

4362c07

sentry Bot reviewed Jul 22, 2026

View reviewed changes

cursor Bot reviewed Jul 22, 2026

View reviewed changes

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lbloder commented May 11, 2026

📜 Description

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

🔮 Next steps

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sentry Bot commented May 11, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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📲 Install Builds

Android

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Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

Previous results on branch: feat/log4j-autoinstrumentation

Startup times

App size

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lbloder commented May 12, 2026

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cursor Bot Jul 21, 2026

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Incomplete existing appender check

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cursor Bot Jul 22, 2026

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Duplicate events with nested loggers

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lbloder commented Jul 24, 2026

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sentry Bot commented May 11, 2026 •

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