java-code-reviewlisted

# Java Code Review Skill Systematic code review checklist for Java projects. ## When to Use - User says "review this code" / "check this PR" / "code review" - Before merging a PR - After implementing a feature ## Review Strategy 1. **Quick scan** - Understand intent, identify scope 2. **Checklist pass** - Go through each category below 3. **Summary** - List findings by severity (Critical → Minor) ## Output Format ```markdown ## Code Review: [file/feature name] ### Critical - [Issue description + line reference + suggestion] ### Improvements - [Suggestion + rationale] ### Minor/Style - [Nitpicks, optional improvements] ### Good Practices Observed - [Positive feedback - important for morale] ``` --- ## Review Checklist ### 1. Null Safety **Check for:** ```java // ❌ NPE risk String name = user.getName().toUpperCase(); // ✅ Safe String name = Optional.ofNullable(user.getName()) .map(String::toUpperCase) .orElse(""); // ✅ Also safe (early return) if (user.getName() == null) { return ""; } return user.getName().toUpperCase(); ``` **Flags:** - Chained method calls without null checks - Missing `@Nullable` / `@NonNull` annotations on public APIs - `Optional.get()` without `isPresent()` check - Returning `null` from methods that could return `Optional` or empty collection **Suggest:** - Use `Optional` for return types that may be absent - Use `Objects.requireNonNull()` for constructor/method params - Return empty collections instead of null: `Collections.