All 94 skillsLanguages11 of 12
stryx:java
When writing, fixing or upgrading Java code: builds, Spring Boot, tests, version moves.
/stryx:javaInside its piece: 11 specks, one for each file on its shelf. Its eleven group-mates glow on the open book behind it. The light splits toward green, the band of Languages.
In numbers
counted 2026-10-12 in the installed set- 9reference files
- 11files in the skill
- 169KB on disk
- 9chapters
- 1agent works by this book
Use it when
in the skill’s own wordsWhen writing, reviewing, fixing or upgrading Java code or JVM services
- records
- sealed types
- switch patterns
- Optional
- Virtual threads, pinning
- Maven (pom.xml, mvnw, surefire, BOMs) or Gradle (build.gradle, gradlew, toolchains) builds of Java projects
- Spring Boot 3 or 4 (starters, @ConfigurationProperties, @Transactional, JPA, Hibernate, Lombok, Jackson 3)
- JUnit 5 or 6
- Mockito
- AssertJ
- @WebMvcTest
- @DataJpaTest
- @MockitoBean
- Testcontainers
- moving between Java 11
- 17
- 21 and 25
- javax to jakarta
- Spring Boot 3 to 4
- Also when the user says
- jdk
- jvm
- maven
- gradle
- Spring Boot
- junit or mockito
- says java in a repo with pom.xml
- build.gradle or .java files
Not for
another skill does it- JavaScript or TypeScript, even when shortened to "java"→ stryx:typescript, stryx:react
- The TDD method and coverage targets→ stryx:test
- Language-neutral refactoring steps→ stryx:refactor
- Gradle errors inside a React Native or Flutter app→ stryx:react-native, stryx:flutter
- A failure whose cause is unknown→ stryx:debug
Inside the book
9 chapters, by title only- Choose the approach
- The Java protocol
- Model data so the compiler checks it
- Virtual threads (21+)
- Builds: Maven and Gradle
- Spring Boot
- Tests
- Upgrades
- When it fails
Its helper
1 agent works by this book- stryx:perf-agentWhen an app needs a speed audit, or one named thing must get measurably faster.
Works with
the skills it names most- stryx:debug→Something is broken: a bug, an error, a crash, a failing test or wrong data.
- stryx:refactor→When code should be tidied or split without changing what it does.
- stryx:test→When tests must be written or fixed, or you want the test written first (TDD).
- stryx:verify→When Claude is about to say done, fixed or ready to commit: fresh proof comes first.
- stryx:ai-power→When you are not sure which skill fits, or you say "load aipower": it is the map of all skills.
- stryx:architect→When the hard part is structure: how the parts of a system fit, and the trade-offs between designs.
Claude loads it by itself when the moment comes; by hand, type the line at the top. It comes with the whole set: Installs all 94 skills, 32 agents and the brain program as one set. The skill’s own text is private source and is not shown here.