Java Review

Review the Java code I've selected or provided. Follow these steps:

Step 1 — Detect Java version

Check the project for pom.xml (look for <java.version> or <maven.compiler.source>) or build.gradle (look for sourceCompatibility). If not found, ask: "What Java version are you targeting? (8, 11, 17, 21, or other)"

Step 2 — Review for bugs and correctness

• Null safety: flag unguarded dereferences; suggest Optional<T> (Java 8+) for values that may be absent
• Resource leaks: flag unclosed InputStream, Connection, PreparedStatement; suggest try-with-resources
• equals/hashCode: if one is overridden without the other, flag it
• Collection mutation: flag modification of a collection while iterating over it
• Thread safety: flag shared mutable fields accessed from multiple threads without synchronization
• Off-by-one: review loop bounds and index access

Step 3 — Review naming and style

• Classes/interfaces: must be PascalCase
• Methods/variables: must be camelCase
• Constants (static final): must be SCREAMING_SNAKE_CASE
• Flag single-letter variable names outside of loop counters (i, j, k)
• Flag abbreviations that reduce clarity (e.g., usr → user, mgr → manager)

Step 4 — Review Java idioms (version-aware)

For each suggestion involving a version-gated feature, state: "Requires Java X+"

• Java 8+: suggest streams/lambdas over verbose imperative loops where clarity improves
• Java 8+: suggest try-with-resources for Closeable resources
• Java 10+: suggest var where the type is obvious from the right-hand side
• Java 16+: suggest records for classes that are pure data holders with no behaviour
• Java 17+: suggest sealed classes for fixed hierarchies; pattern matching for instanceof chains

Step 5 — Review code smells

• Methods longer than 20 lines: suggest extracting to named helper methods
• Classes with more than one clear responsibility: suggest splitting
• Magic numbers/strings: suggest named constants
• Deep nesting (more than 3 levels): suggest early returns or extraction

Output format

Respond with:

1. Summary — 1–2 sentences overall assessment
2. Issues — grouped by severity:
   • 🔴 Critical (bugs, resource leaks, thread safety)
   • 🟡 Warning (naming, missing equals/hashCode, raw types)
   • 🔵 Suggestion (idiom improvements, version-gated enhancements)
3. Strengths — what is done well (at least one observation)

Be concise. Each issue: one sentence description + one-line fix example.

Next Steps

After completing this review, offer these follow-up actions based on findings:

• If structural issues found (long methods, god classes) → suggest running /java-refactor
• If missing or inadequate tests found → suggest running /java-test
• If security issues found (SQL concat, hardcoded secrets, weak crypto) → suggest delegating to the java-security-reviewer agent
• If performance issues found (N+1, unbounded queries, String concatenation in loops) → suggest delegating to the java-performance-reviewer agent
• If Javadoc is missing on public API → suggest running /java-docs