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Tutorial: Java Spring Boot API

What This Tutorial Will Cover

Section titled “What This Tutorial Will Cover”

When Java support lands, this tutorial will walk through:

  1. Creating a minimal Spring Boot REST API with GET /health and GET /greet endpoints
  2. Writing JUnit 5 tests and configuring JaCoCo to produce an XML coverage report
  3. Running nolapse init --repo . --lang java to create the baseline from the JaCoCo report
  4. Simulating a coverage regression by removing a test method
  5. Running nolapse run --repo . --lang java and seeing it exit 1
  6. Adding a GitHub Actions workflow with Maven or Gradle that gates PRs on coverage

Expected Project Structure

Section titled “Expected Project Structure”
hello-spring/
├── src/
│   ├── main/java/com/example/hello/
│   │   ├── HelloController.java
│   │   └── HelloApplication.java
│   └── test/java/com/example/hello/
│       └── HelloControllerTest.java
├── pom.xml
├── .audit/
│   └── coverage/
│       └── baseline.md
└── nolapse.yaml

Expected Commands (Once Available)

Section titled “Expected Commands (Once Available)”

Build and test with Maven

Section titled “Build and test with Maven”
Terminal window
mvn verify

JaCoCo generates target/site/jacoco/jacoco.xml. nolapse will read this file.

Initialise

Section titled “Initialise”
Terminal window
nolapse init --repo . --lang java

Run a check

Section titled “Run a check”
Terminal window
nolapse run --repo . --lang java

GitHub Actions workflow (Maven)

Section titled “GitHub Actions workflow (Maven)”
name: Coverage check


on:
  pull_request:


jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0


      - name: Set up Java
        uses: actions/setup-java@v4
        with:
          java-version: "21"
          distribution: temurin


      - name: Build and test
        run: mvn verify


      - name: Run nolapse
        uses: nolapse/nolapse-action@v1
        with:
          repo-token: ${{ secrets.GITHUB_TOKEN }}
          lang: java
          warn-threshold: "0.5"
          fail-threshold: "1.0"

JaCoCo Configuration

Section titled “JaCoCo Configuration”

nolapse will read the JaCoCo XML report. Add the JaCoCo plugin to pom.xml:

<plugin>
  <groupId>org.jacoco</groupId>
  <artifactId>jacoco-maven-plugin</artifactId>
  <version>0.8.11</version>
  <executions>
    <execution>
      <goals><goal>prepare-agent</goal></goals>
    </execution>
    <execution>
      <id>report</id>
      <phase>verify</phase>
      <goals><goal>report</goal></goals>
    </execution>
  </executions>
</plugin>

Get Notified

Section titled “Get Notified”

Watch the nolapse changelog for the Java runner release. Once available, this tutorial will be updated with full working commands and example output.

See Also

Section titled “See Also”