Add FindThreadGroupUsages recipe (RSPEC-S3014) - #1063
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Marks uses of `java.lang.ThreadGroup`, which was originally intended to help with thread management but has serious design flaws: most methods are deprecated or unsafe, and modern code should use `java.util.concurrent.ExecutorService` instead. Sites flagged: - `new ThreadGroup(...)` constructor calls - `Thread.getThreadGroup()` method calls - Method invocations on `ThreadGroup` receivers Search-only. Migrating off `ThreadGroup` typically requires introducing an executor and restructuring how threads are grouped, which is not automatable. Tags the recipe with RSPEC-S3014.
Jammy-Louie
approved these changes
Sep 16, 2026
bblincoe
self-requested a review
September 16, 2026 19:50
bblincoe
approved these changes
Sep 16, 2026
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Summary
Adds a search-only recipe that flags uses of
java.lang.ThreadGroup.ThreadGroupwas originally intended to help with thread management, but its API has serious design flaws — most methods are deprecated or unsafe, and modern code should usejava.util.concurrent.ExecutorServiceinstead.Implements SonarQube RSPEC-S3014.
Design notes
UsesType<>("java.lang.ThreadGroup")ORUsesMethod<>("java.lang.Thread getThreadGroup()")— the visitor only walks CUs that could match.new ThreadGroup(...)—visitNewClass+TypeUtils.isOfClassType.Thread.getThreadGroup()— dedicatedMethodMatcher.ThreadGroupreceiver (e.g.group.activeCount()) — checksm.getSelect().getType().ThreadGrouptypically requires introducing an executor and restructuring how threads are grouped; not automatable.estimatedEffortPerOccurrence = 30 minutes— realistic manual fix cost, higher than a call-removal recipe.Files
src/main/java/org/openrewrite/staticanalysis/FindThreadGroupUsages.javasrc/test/java/org/openrewrite/staticanalysis/FindThreadGroupUsagesTest.java— 5 testssrc/main/resources/META-INF/rewrite/recipes.csv— regenerated (single-row addition, no drift)Test plan
./gradlew compileJava— passes./gradlew test --tests FindThreadGroupUsagesTest— 5/5 green./gradlew recipeCsvGenerate recipeCsvValidateContent— cleanTest coverage
new ThreadGroup("workers")→ flagged (also verifies surroundingnew Thread(group, ...)andt.start()are not flagged) —@DocumentExampleThread.currentThread().getThreadGroup()→ flaggedgroup.activeCount()wheregroupis aThreadGroupparameter → flaggednew Thread(...)/setName/start/interrupt→ not flagged (negative)com.example.ThreadGroupclass → not flagged (confirms FQN matching, not simple-name matching)