111-java-maven-dependencies

# Add Maven dependencies for improved code quality

Add essential Maven dependencies that enhance code quality, safety, and domain modeling through a consultative, question-driven approach. **This is an interactive SKILL**.

**What is covered in this Skill?**

- JSpecify: (nullness annotations, `provided` scope)
- Error Prone + NullAway: (enhanced static analysis with compile-time null checking)
- VAVR: (functional programming with Try/Either and immutable collections)
- ArchUnit: (architecture rule enforcement, `test` scope)
- JavaMoney: (Money and Currency API support with JSR 354 and Moneta)

## Constraints

Before adding Maven dependencies, ensure the project is in a valid state. Use a consultative, question-driven flow that adds only what the user selects.

- **MANDATORY**: Run `./mvnw validate` or `mvn validate` before any changes
- **SAFETY**: If validation fails, stop and ask the user to fix issues—do not proceed until resolved
- **BEFORE READING DEPENDENCY REFERENCES**: Run the question flow embedded in this SKILL.md first. Ask one consolidated dependency-selection question, then ask only conditional follow-up questions required by the selected options. Read only the dependency references selected by the user's answers. Use consultative language, present trade-offs, and wait for user responses before implementing

## When to use this skill

- Add Maven dependencies
- Add JSpecify nullness dependencies
- Add Error Prone NullAway dependencies
- Add VAVR functional dependencies
- Add ArchUnit architecture testing dependencies
- Add JavaMoney dependencies

## Workflow

1. **Validate project before changes**

Run `./mvnw validate` or `mvn validate` and stop if validation fails.

2. **Ask dependency assessment questions before reading references**


Run this XML-included question flow before reading any dependency implementation reference. Ask the consolidated dependency-selection question first, wait for the user's answer, and record selected dependency families before continuing. Ask conditional follow-up questions only when required by the selected dependencies.


**Question 1**: Which code-quality dependencies do you want to add?

Options:
- JSpecify (modern nullness annotations, `provided` scope; recommended for new projects)
- Error Prone + NullAway (enhanced compiler analysis and compile-time nullness checking; requires JSpecify)
- VAVR (functional programming support with Try/Either and immutable collections)
- ArchUnit (architecture testing with JUnit 5, `test` scope)
- JavaMoney (Money and Currency API support with JSR 354 and Moneta)
- None
- Other (specify)

**Recommendation**: Select JSpecify for better null-safety annotations. Add Error Prone + NullAway when you want stronger compile-time analysis. Add VAVR only when functional programming patterns are useful for the project. Add ArchUnit when you want automated architecture governance. Add JavaMoney when the domain needs explicit monetary amounts, currencies, formatting, conversion, or precision-safe money calculations.

**Selection notes**:
- If Error Prone + NullAway is selected, also select JSpecify unless the project already has equivalent nullness annotations configured.
- If None is selected, do not add dependency-family references.

---

**Question 2** (conditional): What is your main project package name?

**Note**: This question is asked only if Error Prone + NullAway was selected.

This is needed to configure NullAway to analyze your code. For example, if your classes are in `com.example.myproject`, enter `com.example.myproject`.

**Format**: Use dot notation (e.g., `com.example.myproject` or `org.mycompany.myapp`)

**Example**: `com.example.myproject`


After all applicable questions are answered, confirm the selections and map them to references:

- If JSpecify is selected, read `references/111-java-maven-dependencies-jspecify.md`.
- If enhanced compiler analysis is selected, use the Error Prone + NullAway section from `references/111-java-maven-dependencies-jspecify.md`.
- If VAVR is selected, read `references/111-java-maven-dependencies-vavr.md`.
- If ArchUnit is selected, read `references/111-java-maven-dependencies-archunit.md`.
- If JavaMoney is selected, read `references/111-java-maven-dependencies-javamoney.md`.
- Do not read or apply unselected dependency-family references.


3. **Read selected references and add only selected dependencies**

Read only the selected dependency-family references, then implement only the dependencies, properties, scopes, plugin configuration, and support files chosen by the user while preserving the existing `pom.xml` structure.

4. **Report trade-offs and next checks**

Summarize what was added, why, and any recommended follow-up validations or tooling alignment.

## Reference

For detailed guidance, examples, and constraints, see:

- [references/111-java-maven-dependencies-jspecify.md](references/111-java-maven-dependencies-jspecify.md)
- [references/111-java-maven-dependencies-vavr.md](references/111-java-maven-dependencies-vavr.md)
- [references/111-java-maven-dependencies-archunit.md](references/111-java-maven-dependencies-archunit.md)
- [references/111-java-maven-dependencies-javamoney.md](references/111-java-maven-dependencies-javamoney.md)