### Install and Install Hooks for Pre-commit

Source: https://github.com/jabrena/cursor-rules-java/blob/main/CLAUDE.md

Install the pre-commit tool using pip or brew, then install the git hooks. This setup is required once per clone.

```bash
pip install pre-commit   # or: brew install pre-commit
pre-commit install --install-hooks
```

--------------------------------

### Install Skills with npx

Source: https://github.com/jabrena/cursor-rules-java/blob/main/site-generator/content/blog/2026/03/release-0.12.0.md

Install skills from a repository using the npx skills command. This example shows how to list all skills and add a specific one.

```bash
brew install node
npx skills add jabrena/cursor-rules-java --list
```

```bash
npx skills add https://github.com/jabrena/cursor-rules-java \
--skill 110-java-maven-best-practices
```

--------------------------------

### Setup Async Profiler for Java Applications

Source: https://context7.com/jabrena/cursor-rules-java/llms.txt

Use these scripts to set up async-profiler for Java applications. The `run-java-process-for-profiling.sh` script starts the application with profiling JVM flags, while `profile-java-process.sh` attaches the profiler to a running JVM, offering an interactive menu for CPU, memory, lock, GC, or I/O profiling.

```bash
# Start application with profiling JVM flags:
./run-java-process-for-profiling.sh
```

```bash
# Attach profiler to running JVM (interactive menu):
./profiler/scripts/profile-java-process.sh
# Menu: 1) CPU  2) Memory  3) Lock  4) GC  5) I/O
# Output: profiler/results/cpu-flamegraph-20260115-143022.html
#         profiler/results/recording-20260115-143022.jfr
```

--------------------------------

### Install and List Skills with npx

Source: https://github.com/jabrena/cursor-rules-java/blob/main/documentation/GETTING-STARTED-SKILLS.md

Use npx commands to manage Skills. Ensure Node.js and npm are installed first.

```bash
#To install npx
brew install node
sudo apt install nodejs npm

npx skills --help
npx skills add jabrena/cursor-rules-java --list
npx skills add jabrena/cursor-rules-java --all --agent cursor
npx skills add jabrena/cursor-rules-java --all --agent claude-code
```

--------------------------------

### Example System Prompt Structure for Java

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/courses/system-prompts-java/module-1-foundations.html

Illustrates the typical structure of a system prompt for Java development, including role, goal, constraints, and output format. Useful for guiding AI assistants in tasks like pom.xml modifications.

```markdown
## Role
You are a Senior Java Developer...

## Goal
Your task is to...

## Constraints
- Follow Maven best practices
- Use Java 21+ features
- Ensure backward compatibility

## Output Format
- Generate pom.xml modifications
- Provide explanation of changes
- Include validation steps
```

--------------------------------

### Sakila Database Setup and API Interaction

Source: https://github.com/jabrena/cursor-rules-java/blob/main/examples/spring-boot-demo/requirements/original/README.md

This sequence of bash commands demonstrates how to run the Sakila PostgreSQL database in a Docker container, start the Spring Boot application, fetch films via a cURL request, and stop the database container.

```bash
docker run -e POSTGRES_PASSWORD=sakila --rm --name sakiladb -p 5432:5432 -d "sakiladb/postgres"
./mvnw spring-boot:run
curl http://localhost:8080/api/v1/films
docker stop sakiladb
```

--------------------------------

### Install Jira CLI on Linux

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/044-planning-jira/references/044-planning-jira.md

Install the Jira CLI on Linux using the apt package manager or by downloading and manually installing the binary.

```bash
sudo apt-get install jira-cli
```

```bash
chmod +x jira
/usr/local/bin/jira
```

--------------------------------

### Install OpenSpec CLI using npm

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/042-planning-openspec/SKILL.md

Provides installation guidance for the OpenSpec CLI on different operating systems using npm. Use this when the CLI is not found.

```bash
npm install -g @openspec/cli
```

--------------------------------

### File Checklist Table Example

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills-generator/src/main/resources/skill-references/assets/java-design-plan-template.md

Example structure for the File Checklist table, listing the order and file path for project files.

```markdown
| Order | File |
|-------|------|
| 1 | `path/to/File1.java` |
| 2 | `path/to/Test.java` |
| 3 | `path/to/Impl.java` |
```

--------------------------------

### Install and Use Pre-commit Hooks

Source: https://github.com/jabrena/cursor-rules-java/blob/main/CONTRIBUTING.md

Install pre-commit for local development. This ensures code quality and adherence to commit message conventions before committing.

```bash
pip install pre-commit
pre-commit install --install-hooks
```

```bash
brew install pre-commit
pre-commit install --install-hooks
```

--------------------------------

### Install All Cursor Rules Java Skills with Agent

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/blog/2026/03/release-0.12.0.html

Install all available Skills from the Cursor Rules Java repository and associate them with the 'cursor' agent using 'npx skills install'.

```bash
npx skills install jabrena/cursor-rules-java --all --agent cursor
```

--------------------------------

### Run Local Blog Preview

Source: https://github.com/jabrena/cursor-rules-java/blob/main/DEVELOPER.md

Builds and serves the project's blog locally for previewing changes.

```bash
# Run blog in local
./mvnw clean generate-resources jbake:inline -pl site-generator -P local-preview
```

--------------------------------

### Setup Timer and Clock

Source: https://github.com/jabrena/cursor-rules-java/blob/main/documentation/conferences/codemotion-madrid-2026/plugin/notes/speaker-view.html

Initializes and starts updating the timer and clock elements, including pacing information, by fetching slide timings.

```javascript
function setupTimer() {
    var start = new Date(),
        timeEl = document.querySelector( '.speaker-controls-time' ),
        clockEl = timeEl.querySelector( '.clock-value' ),
        hoursEl = timeEl.querySelector( '.hours-value' ),
        minutesEl = timeEl.querySelector( '.minutes-value' ),
        secondsEl = timeEl.querySelector( '.seconds-value' ),
        pacingTitleEl = timeEl.querySelector( '.pacing-title' ),
        pacingEl = timeEl.querySelector( '.pacing' ),
        pacingHoursEl = pacingEl.querySelector( '.hours-value' ),
        pacingMinutesEl = pacingEl.querySelector( '.minutes-value' ),
        pacingSecondsEl = pacingEl.querySelector( '.seconds-value' );

    var timings = null;
    getTimings( function ( _timings ) {
        timings = _timings;
        if (_timings !== null) {
            pacingTitleEl.style.removeProperty('display');
            pacingEl.style.removeProperty('display');
```

--------------------------------

### Skill File Structure Example

Source: https://github.com/jabrena/cursor-rules-java/blob/main/site-generator/content/blog/2026/03/release-0.12.0.md

Illustrates the standard directory structure for a Skill, including required and optional components.

```bash
my-skill/
├── SKILL.md          # Required: instructions + metadata
├── scripts/          # Optional: executable code
├── references/       # Optional: documentation
└── assets/           # Optional: templates, resources
```

--------------------------------

### Quarkus Integration Test

Source: https://context7.com/jabrena/cursor-rules-java/llms.txt

Example of a Quarkus integration test using `@QuarkusTest`. This setup verifies REST endpoint behavior and response validation.

```java
import io.quarkus.test.junit.QuarkusTest;
import org.junit.jupiter.api.Test;
import static io.restassured.RestAssured.given;
import static org.hamcrest.Matchers.equalTo;

// Skill 422 — Quarkus integration test:
@QuarkusTest
class GodAnalysisIT {
  @Test
  void shouldReturn200() {
    given().when().get("/api/v1/gods/Zeus/analysis")
           .then().statusCode(200).body("origin", equalTo("Greek"));
  }
}
```

--------------------------------

### Setup Timer and Clock

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/codemotion-madrid-2026/plugin/notes/speaker-view.html

Initializes and starts updating the timer and clock elements. It retrieves slide timings first and then sets up intervals for updating the display.

```javascript
function setupTimer() {
var start = new Date(), timeEl = document.querySelector( '.speaker-controls-time' ), clockEl = timeEl.querySelector( '.clock-value' ), hoursEl = timeEl.querySelector( '.hours-value' ), minutesEl = timeEl.querySelector( '.minutes-value' ), secondsEl = timeEl.querySelector( '.seconds-value' ), pacingTitleEl = timeEl.querySelector( '.pacing-title' ), pacingEl = timeEl.querySelector( '.pacing' ), pacingHoursEl = pacingEl.querySelector( '.hours-value' ), pacingMinutesEl = pacingEl.querySelector( '.minutes-value' ), pacingSecondsEl = pacingEl.querySelector( '.seconds-value' );
var timings = null;
getTimings( function ( _timings ) {
timings = _timings;
if (_timings !== null) {
pacingTitleEl.style.removeProperty('display');
pacingEl.style.removeProperty('display');
// ... rest of the timer setup
```

--------------------------------

### Install Cursor Rules Java CLI

Source: https://github.com/jabrena/cursor-rules-java/blob/main/site-generator/content/blog/2026/03/release-0.12.0.md

Use this command to initialize the project with System prompts from the repository.

```bash
jbang setup@jabrena init \
--cursor https://github.com/jabrena/cursor-rules-java
```

--------------------------------

### Micronaut Integration Test with Testcontainers

Source: https://context7.com/jabrena/cursor-rules-java/llms.txt

Example of a Micronaut integration test using `@MicronautTest` and `TestPropertyProvider` to integrate with Testcontainers for PostgreSQL. This requires the `postgres` container to be started.

```java
import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
import io.micronaut.test.support.TestPropertyProvider;
import org.junit.jupiter.api.extension.ExtensionContext;
import org.testcontainers.containers.PostgreSQLContainer;
import java.util.Map;

// Skill 522 — Micronaut integration test:
@MicronautTest
class GodAnalysisIT implements TestPropertyProvider {
  @Override
  public Map<String, String> getProperties() {
    postgres.start();
    return Map.of("datasources.default.url", postgres.getJdbcUrl());
  }
  static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:16");
}
```

--------------------------------

### Run Profiling Script with Help

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/courses/profile-memory-leak/module-1-foundations.html

Execute the main profiling script with the --help flag to display available options and usage instructions.

```bash
./run-java-process-for-profiling.sh --help
```

--------------------------------

### Ambiguous Flyway Configuration Example

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/413-frameworks-quarkus-db-migrations-flyway/references/413-frameworks-quarkus-db-migrations-flyway.md

Illustrates a problematic configuration where multiple datasources are defined but only a single, shared Flyway location is specified, leading to ambiguity in which schema gets migrated.

```properties
# Bad: two datasources but only one Flyway location — ambiguous or wrong schema gets migrated
quarkus.datasource.orders.jdbc.url=jdbc:postgresql://localhost/orders
quarkus.datasource.audit.jdbc.url=jdbc:postgresql://localhost/audit
quarkus.flyway.locations=classpath:db/migration
```

--------------------------------

### Spring Boot Demo Application README.md Structure

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/courses/system-prompts-java/module-6-documentation.html

This is an example structure for a README.md file generated for a Spring Boot demo application, including overview, features, and quick start instructions.

```markdown
# Spring Boot Demo Application

## Overview
A comprehensive Spring Boot demonstration application showcasing enterprise-grade development practices including REST APIs, data persistence, security, and testing.

## Features
- RESTful API endpoints for user management
- JPA-based data persistence with H2 database
- Spring Security integration
- Comprehensive test coverage
- Docker support for containerization

## Quick Start

### Prerequisites
- Java 21 or higher
- Maven 3.8+
- Docker (optional)

### Running the Application
```bash
# Clone the repository
git clone <repository-url>
cd spring-boot-demo

# Run with Maven
./mvnw spring-boot:run

# Or build and run JAR
./mvnw clean package
java -jar target/spring-boot-demo-*.jar

```

--------------------------------

### Build Plan and Help Commands

Source: https://github.com/jabrena/cursor-rules-java/blob/main/DEVELOPER.md

These commands help in understanding the build plan and retrieving project information, such as available profiles.

```bash
./mvnw buildplan:list-plugin
./mvnw buildplan:list-phase
./mvnw help:all-profiles
./mvnw help:active-profiles
```

--------------------------------

### Initialize OpenSpec Project

Source: https://github.com/jabrena/cursor-rules-java/blob/main/site-generator/content/blog/2026/04/release-0.14.0.md

Use this command to set up a new OpenSpec project structure in your workspace.

```bash
openspec init
```

--------------------------------

### Incorrect Main Application Class: Missing @SpringBootApplication

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/301-frameworks-spring-boot-core/references/301-frameworks-spring-boot-core.md

This example demonstrates an incorrect setup where `@SpringBootApplication` is missing, leading to the loss of Spring Boot conveniences. Manual context creation is shown.

```java
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainApplication {
    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext();
    }
}
```

--------------------------------

### Setup Presentation Timer and Clock

Source: https://github.com/jabrena/cursor-rules-java/blob/main/documentation/conferences/dvbe25/plugin/notes/speaker-view.html

Initializes and updates the presentation timer and clock elements. It retrieves slide timings and starts an interval to update the displayed time, hours, minutes, and seconds.

```javascript
function setupTimer() {
var start = new Date(),
timeEl = document.querySelector( '.speaker-controls-time' ),
clockEl = timeEl.querySelector( '.clock-value' ),
hoursEl = timeEl.querySelector( '.hours-value' ),
minutesEl = timeEl.querySelector( '.minutes-value' ),
secondsEl = timeEl.querySelector( '.seconds-value' ),
pacingTitleEl = timeEl.querySelector( '.pacing-title' ),
pacingEl = timeEl.querySelector( '.pacing' ),
pacingHoursEl = pacingEl.querySelector( '.hours-value' ),
pacingMinutesEl = pacingEl.querySelector( '.minutes-value' ),
pacingSecondsEl = pacingEl.querySelector( '.seconds-value' );
var timings = null;
getTimings( function ( _timings ) {
timings = _timings;
if (_timings !== null) {
pacingTitleEl.style.removeProperty('display');
pacingEl.style.removeProperty('display');
```

--------------------------------

### Execute Profiling Script with Help

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/courses/profile-memory-leak/module-1-foundations.html

Run the specific Java process profiling script with the --help flag to understand its options and how to initiate a profiling session.

```bash
./profile-java-process.sh --help
```

--------------------------------

### Setup Timer and Clock

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/dvbe25/plugin/notes/speaker-view.html

Initializes and updates the presentation timer and clock display. It retrieves slide timings and starts an interval to update the elapsed time, remaining time, and pacing information.

```javascript
function setupTimer() {
var start = new Date(),
timeEl = document.querySelector( '.speaker-controls-time' ),
clockEl = timeEl.querySelector( '.clock-value' ),
hoursEl = timeEl.querySelector( '.hours-value' ),
minutesEl = timeEl.querySelector( '.minutes-value' ),
secondsEl = timeEl.querySelector( '.seconds-value' ),
pacingTitleEl = timeEl.querySelector( '.pacing-title' ),
pacingEl = timeEl.querySelector( '.pacing' ),
pacingHoursEl = pacingEl.querySelector( '.hours-value' ),
pacingMinutesEl = pacingEl.querySelector( '.minutes-value' ),
pacingSecondsEl = pacingEl.querySelector( '.seconds-value' );
var timings = null;
getTimings( function ( _timings ) {
timings = _timings;
if (_timings !== null) {
pacingTitleEl.style.removeProperty('display');
pacingEl.style.removeProperty('display');
// ... rest of the timer setup
```

--------------------------------

### Start CPU Hotspot Identification JFR Recording

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/blog/2025/09/jfr-modern-java-profiling.html

Begin a JFR recording to identify CPU hotspots. This setup focuses on execution samples, CPU time, and thread CPU load.

```shell
jcmd <pid> JFR.start name=cpu-analysis duration=60s \
  "jdk.ExecutionSample#enabled=true" \
  "jdk.CPUTimeSample#enabled=true" \
  "jdk.ThreadCPULoad#enabled=true" \
  filename=cpu-hotspots.jfr
```

--------------------------------

### Good Example: Paginated, Sorted, and Filtered Product List

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/302-frameworks-spring-boot-rest/references/302-frameworks-spring-boot-rest.md

Demonstrates proper handling of pagination, sorting, and filtering for product listings. Enforces page size limits and whitelists sortable properties to prevent injection vulnerabilities. Optionally includes Link headers for discoverability.

```java
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.web.PageableDefault;
import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.Set;

@RestController
@RequestMapping("/api/v1/products")
class ProductQueryController {

    private static final int MAX_PAGE_SIZE = 100;
    private static final Set<String> ALLOWED_SORT = Set.of("createdAt", "name", "price");

    @GetMapping
    ResponseEntity<Page<ProductDTO>> list(
            @RequestParam(required = false) String category,
            @PageableDefault(size = 20, sort = "createdAt") Pageable pageable) {
        if (pageable.getPageSize() > MAX_PAGE_SIZE) {
            throw new IllegalArgumentException("page size exceeds maximum of " + MAX_PAGE_SIZE);
        }
        pageable.getSort().forEach(order -> {
            if (!ALLOWED_SORT.contains(order.getProperty())) {
                throw new IllegalArgumentException("sort by '" + order.getProperty() + "' is not allowed");
            }
        });
        Page<ProductDTO> page = Page.empty(pageable);
        return ResponseEntity.ok()
            .header(HttpHeaders.LINK, "</api/v1/products?page=1&size=20>; rel=\"next\"")
            .body(page);
    }
}
class ProductDTO { }
```

--------------------------------

### Execute Profiling Script with Help

Source: https://github.com/jabrena/cursor-rules-java/blob/main/site-generator/content/courses/profile-memory-leak/module-1-foundations.md

Navigate to the profiler scripts directory and execute the main profiling script with the --help flag. This displays the available profiling options and configurations.

```bash
cd profiler/scripts
./profile-java-process.sh --help
```

--------------------------------

### Generated Task List Example

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/blog/2026/03/release-0.13.0.html

Shows a detailed task list generated by an agent, including phases, TDD status, milestones, and parallel execution information. This list guides the development process.

```markdown
## Task List

| # | Task | Phase | TDD | Milestone | Parallel | Status |
|---|------|-------|-----|-----------|----------|--------|
| 1 | Extend **implementation2** `pom.xml`: `quarkus-rest`, JDBC PostgreSQL, Flyway, scheduler, SmallRye OpenAPI, outbound HTTP client dep (or JDK client only), `rest-assured`, Testcontainers, Failsafe for `*IT`; plan `%test` datasource | Setup | | | A1 | Done |
| 2 | **RED:** `GreekGodsApiIT` — REST Assured `GET /api/v1/gods/greek` expects **200**, JSON array, 20 canonical names (set equality), no duplicates (fails until slice exists) | RED | Test | | A1 | Done |
| 3 | **GREEN:** Flyway migration matching [schema.sql](../design/schema.sql); seed 20 names (Flyway test data / IT setup); JDBC repository `findAllNamesOrdered()`; Jakarta REST resource; no external call on read path | GREEN | Impl | | A1 | Done |
| 4 | **Refactor:** Structured logging (read path): request or repo boundaries per team standard | Refactor | | | A1 | Done |
| 5 | **Refactor:** `ExceptionMapper` for persistence failures → 500 `application/problem+json`; empty DB IT → 200 `[]`; invalid JDBC / container stop for 500 shape; external base URL property (no hard-coded URL) | Refactor | | | A1 | Done |
| 6 | **Verify:** `./mvnw clean verify` in **implementation2**; fix failures before M2 | Verify | | milestone | A1 | Done |
```

--------------------------------

### Clone Repository and Navigate

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/courses/system-prompts-java/index.html

Clone the project repository to your local machine and navigate into the project directory.

```bash
git clone https://github.com/jabrena/cursor-rules-java.git
cd cursor-rules-java
```

--------------------------------

### Add Cursor Rules Java Skills using 'npx skills'

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/blog/2026/03/release-0.12.0.html

Install Skills from the Cursor Rules Java repository using the 'npx skills' command. This example shows how to add a specific skill.

```bash
brew install node
npx skills add jabrena/cursor-rules-java --list
```

--------------------------------

### Application Bootstrap with Micronaut.run

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/501-frameworks-micronaut-core/references/501-frameworks-micronaut-core.md

Start the embedded Netty server and application context with `Micronaut.run`. Avoid embedding business logic in `main`.

```java
import io.micronaut.runtime.Micronaut;

public final class Application {

    public static void main(String[] args) {
        Micronaut.run(Application.class, args);
    }
}
```

```java
import io.micronaut.runtime.Micronaut;

public final class Application {

    public static void main(String[] args) {
        // Bad: business work in main — untestable and couples startup to domain
        new OrderBacklogProcessor().drainAllQueues();
        Micronaut.run(Application.class, args);
    }
}
```

--------------------------------

### Base Quarkus Acceptance Test Setup

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/423-frameworks-quarkus-testing-acceptance-tests/references/423-frameworks-quarkus-testing-acceptance-tests.md

Abstract base class for Quarkus acceptance tests. It uses `@QuarkusTest` to start the application once per test suite and integrates `PostgreSQLLifecycleManager` and `WireMockLifecycleManager` to provide real infrastructure dependencies.

```java
// Base acceptance test: Quarkus starts once; containers and WireMock are shared across tests
@QuarkusTest
@QuarkusTestResource(PostgreSQLLifecycleManager.class)
@QuarkusTestResource(WireMockLifecycleManager.class)
abstract class BaseAcceptanceTest {

    @BeforeEach
    void resetWireMock() {
        WireMockLifecycleManager.wireMockServer.resetAll(); // isolate stubs between test methods
    }
}

```

--------------------------------

### Incorrect Test Suffix with Spring Boot Example

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/322-frameworks-spring-boot-testing-integration-tests/references/322-frameworks-spring-boot-testing-integration-tests.md

Illustrates a test class named `*Test` but configured with `@SpringBootTest` and a real container. This incorrect setup leads to Surefire executing it in the wrong phase and bypasses Failsafe's verification.

```java
// Bad: class name ends in "Test" but uses @SpringBootTest with a real container —
// Surefire will execute it in the wrong phase; Failsafe's "verify" safety net is bypassed,
// so a container failure won't fail the build at the right gate.
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@Testcontainers
class OrderApiTest {   // ← should be OrderApiIT

    @Container
    @ServiceConnection
    static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:16-alpine");

    @Test
    void shouldCreateOrder() { ... }
}
```

--------------------------------

### Good Test Example: CORRECT Boundary Conditions in Java

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/130-java-testing-strategies/references/130-java-testing-strategies.md

Demonstrates comprehensive boundary condition testing using the CORRECT principles (Conformance, Ordering, Range, Existence, Cardinality, Time) for user validation.

```java
public class UserValidationTest {
    private final UserValidation validator = new UserValidation();

    // Testing Range for age
    @Test
    void isAgeValid_ageAtLowerBound_returnsTrue() {
        assertThat(validator.isAgeValid(18)).isTrue();
    }

    @Test
    void isAgeValid_ageAtUpperBound_returnsTrue() {
        assertThat(validator.isAgeValid(120)).isTrue();
    }

    @Test
    void isAgeValid_ageBelowLowerBound_returnsFalse() {
        assertThat(validator.isAgeValid(17)).isFalse();
    }

    // Testing Conformance for email
    @ParameterizedTest
    @ValueSource(strings = {"user@example.com", "user.name@sub.example.co.uk"})
    void isValidEmailFormat_validEmails_returnsTrue(String email) {
        assertThat(validator.isValidEmailFormat(email)).isTrue();
    }

    @ParameterizedTest
    @ValueSource(strings = {"userexample.com", "user@", "@example.com"})
    void isValidEmailFormat_invalidEmails_returnsFalse(String email) {
        assertThat(validator.isValidEmailFormat(email)).isFalse();
    }

    // Testing Existence for username
    @Test
    void processUsername_nullUsername_returnsFalse() {
        assertThat(validator.processUsername(null)).isFalse();
    }

    @Test
    void processUsername_emptyUsername_returnsFalse() {
        assertThat(validator.processUsername("")).isFalse();
    }
}
```

--------------------------------

### Create Comprehensive Solutions Document

Source: https://github.com/jabrena/cursor-rules-java/blob/main/site-generator/content/courses/profile-memory-leak/module-3-analysis.md

Generates a markdown file for profiling solutions and recommendations. It includes quick wins and medium-term improvements, with placeholders for date and specific code changes.

```bash
# Create comprehensive solutions document
DATE_SUFFIX=$(date +%Y%m%d)
cat > solutions/profiling-solutions-${DATE_SUFFIX}.md << 'EOF'
# Profiling Solutions and Recommendations - [DATE]

## Quick Wins (Low effort, High impact)

### Solution 1: Enable Fixed Controller Implementation
- **Problem**: Critical memory leaks in CocoController causing unbounded growth
- **Solution**: Switch to NoCocoController using coco=false configuration
- **Expected Impact**: Eliminate memory leaks immediately, stabilize memory usage
- **Implementation Effort**: 5 minutes (configuration change)
- **Code Changes**:
  ```properties
  # application.properties
  coco=false
  ```
- **Validation**: Memory usage should stabilize within 30 minutes of change

### Solution 2: Implement Collection Bounds
- **Problem**: ArrayList grows without limits leading to memory exhaustion
- **Solution**: Add MAX_OBJECTS constant and bounds checking
- **Expected Impact**: Cap memory usage, provide graceful degradation
- **Implementation Effort**: 30 minutes (add bounds checking)
- **Code Changes**:
  ```java
  private static final int MAX_OBJECTS = 10000;

  if (objects.size() >= MAX_OBJECTS) {
      return ResponseEntity.badRequest()
          .body("Maximum objects limit reached: " + MAX_OBJECTS);
  }
  ```

## Medium-term Improvements

EOF

```

--------------------------------

### Serve Website Locally with Maven

Source: https://github.com/jabrena/cursor-rules-java/blob/main/CLAUDE.md

Run this command to serve the project's website locally, mirroring the GitHub Pages setup. It uses JBake to generate and serve the site from the `site-generator` module.

```bash
./mvnw clean generate-resources jbake:inline -pl site-generator -P local-preview
```

--------------------------------

### Navigate to Demo Project Directory

Source: https://github.com/jabrena/cursor-rules-java/blob/main/docs/courses/profile-memory-leak/module-1-foundations.html

Change the current directory to the root of the demo project to execute subsequent commands.

```bash
cd ./cursor-rules-java/examples/spring-boot-memory-leak-demo
```

--------------------------------

### Incomplete Spring Boot slice test without mock dependencies

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/321-frameworks-spring-boot-testing-unit-tests/references/321-frameworks-spring-boot-testing-unit-tests.md

This example demonstrates a failing slice test where essential mock dependencies are missing. The test context will fail to start if required beans like OrderService or PaymentService are not provided via @MockBean or similar mechanisms.

```java
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@WebMvcTest(OrderController.class)
class OrderControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    void shouldCreateOrder() throws Exception {
        mockMvc.perform(post("/api/orders")
                .contentType(MediaType.APPLICATION_JSON)
                .content("{}"))
            .andExpect(status().isCreated());
    }
}
```

--------------------------------

### Semantic HTTP Methods

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/502-frameworks-micronaut-rest/references/502-frameworks-micronaut-rest.md

This example demonstrates the correct usage of HTTP methods (GET, POST, PUT, PATCH, DELETE) for CRUD operations in a Micronaut controller. It maps operations to the appropriate HTTP verb to ensure server state is managed correctly and to follow RESTful principles.

```APIDOC
## GET /users/{id}

### Description
Retrieves a user by their ID.

### Method
GET

### Endpoint
/users/{id}

### Parameters
#### Path Parameters
- **id** (String) - Required - The unique identifier of the user.

### Response
#### Success Response (200)
- **UserDto** (Object) - The user data transfer object.

### Response Example
```json
{
  "id": "user-123"
}
```

## POST /users

### Description
Creates a new user.

### Method
POST

### Endpoint
/users

### Parameters
#### Request Body
- **UserCreateDto** (Object) - Required - The data for creating a new user.
  - **username** (String) - Required - The username for the new user.
  - **email** (String) - Required - The email address for the new user.

### Response
#### Success Response (201)
- **UserDto** (Object) - The created user data transfer object.

### Response Example
```json
{
  "id": "user-456"
}
```

## PUT /users/{id}

### Description
Updates an existing user by their ID.

### Method
PUT

### Endpoint
/users/{id}

### Parameters
#### Path Parameters
- **id** (String) - Required - The unique identifier of the user to update.
#### Request Body
- **UserUpdateDto** (Object) - Required - The updated user data.
  - **username** (String) - Required - The updated username.
  - **email** (String) - Required - The updated email address.

### Response
#### Success Response (200)
- **UserDto** (Object) - The updated user data transfer object.

### Response Example
```json
{
  "id": "user-123"
}
```

## PATCH /users/{id}

### Description
Partially updates an existing user by their ID.

### Method
PATCH

### Endpoint
/users/{id}

### Parameters
#### Path Parameters
- **id** (String) - Required - The unique identifier of the user to partially update.
#### Request Body
- **UserPatchDto** (Object) - Required - The partial update data for the user.
  - **username** (String) - Optional - The updated username.
  - **email** (String) - Optional - The updated email address.

### Response
#### Success Response (200)
- **UserDto** (Object) - The updated user data transfer object.

### Response Example
```json
{
  "id": "user-123"
}
```

## DELETE /users/{id}

### Description
Deletes a user by their ID.

### Method
DELETE

### Endpoint
/users/{id}

### Parameters
#### Path Parameters
- **id** (String) - Required - The unique identifier of the user to delete.

### Response
#### Success Response (204)
No content is returned on successful deletion.
```

--------------------------------

### Run Maven Integration Tests

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/112-java-maven-plugins/references/112-java-maven-plugins.md

Command-line examples for running Maven tests. Use './mvnw verify' to run both unit and integration tests, or './mvnw failsafe:integration-test' to run only integration tests.

```bash
# Run only unit tests
./mvnw test
```

```bash
# Run both unit and integration tests
./mvnw verify
```

```bash
# Run only integration tests
./mvnw failsafe:integration-test
```

--------------------------------

### Inefficient JDBC Repository Test with @SpringBootTest

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/311-frameworks-spring-jdbc/references/311-frameworks-spring-jdbc.md

Avoid using @SpringBootTest for testing JDBC repositories as it loads the entire application context, leading to slow startup times and unnecessary overhead. This example also shows a test that lacks fixture setup, making it dependent on pre-existing database state.

```java
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.List;
import static org.assertj.core.api.Assertions.assertThat;

// Bad: full application context loaded just to test a JDBC repository —
// slow startup, loads web layer and all beans unnecessarily
@SpringBootTest
class ProductRepositoryTest {

    @Autowired
    ProductRepository productRepository;

    @Test
    void findActive() {
        // Bad: no fixture setup — test depends on pre-existing database state
        List<ProductRow> active = productRepository.findActive();
        assertThat(active).isNotEmpty();
    }
}

```

--------------------------------

### Verify OpenSpec Installation

Source: https://github.com/jabrena/cursor-rules-java/blob/main/skills/042-planning-openspec/references/042-planning-openspec.md

Check if OpenSpec is installed and accessible. If not, provides installation instructions using npm.

```bash
openspec --version
```

```bash
npm install -g @fission-ai/openspec@latest
openspec --version
```