java-conventions

- Java 17+ LTS, records for immutable data, sealed classes for restricted hierarchies, pattern matching. - A consistent style guide and auto-formatter (e.g., Google Java Style + google-java-format). Static analysis (e.g., Error Prone + SpotBugs). - Build: Maven or Gradle with wrapper scripts (`mvnw`/`gradlew`). Commit wrapper files. - Testing: JUnit 5 with `@ParameterizedTest`, an assertion library (e.g., AssertJ), a coverage tool (e.g., JaCoCo) at 80%+. - Benchmarking: JMH for microbenchmarks — never use `System.nanoTime()` loops. - Error handling: specific exceptions only, never `catch (Exception)`, use try-with-resources for `AutoCloseable`. - `var` for obvious types, `Optional<T>` for returns (never params/fields), `final` fields by default. - Prefer constructor injection over field injection for DI. Immutable collections: `List.of()`, `Map.of()`. - Streams for collection transforms, `instanceof` pattern matching, switch expressions. - Security: OWASP `dependency-check` Maven/Gradle plugin for CVE scanning. - Dependencies: commit lock files, use BOM for version alignment, avoid `SNAPSHOT` in releases. - Anti-patterns: public fields, mutable static state, raw types, checked exceptions in lambdas.