Fix Failing Java Tests Until Maven Builds Green¶

The Slack message says “BUILD SUCCESS.” Your laptop says otherwise:

[ERROR] Failures:
[ERROR]   AppTest.testAdd:15 expected:<5> but was:<-1>
[INFO] BUILD FAILURE

JUnit caught it. Maven stopped the world. You know the fix is probably one operator in App.java — but between downloading dependencies, re-running Surefire, and waiting for CI, a one-line bug eats an hour.

Kramlipi AI Code Agent closes that loop. It edits your repo with tools and only stops when --verify-cmd exits 0. It does not invent success. If mvn test still reports BUILD FAILURE, the agent keeps working or fails honestly.

This tutorial builds a Maven quickstart under /tmp/java-demo, breaks App.add, and fixes it two ways: prompt mode and bug-fix --log.

What you need¶

chmod +x code-agent
export CODE_AGENT_MODEL=gemini/gemini-2.0-flash
export GEMINI_API_KEY=your-key-here

./code-agent doctor --provider-test

Claude and OpenAI work the same way — set CODE_AGENT_MODEL to an anthropic/… or openai/… string and export the matching key.

Step 1 — Create a failing Maven + JUnit test¶

mkdir -p /tmp/java-demo && cd /tmp/java-demo
git init

mvn archetype:generate -DgroupId=com.example -DartifactId=demo \
  -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

cd demo

cat > src/main/java/com/example/App.java <<'EOF'
package com.example;

public class App {
    public static int add(int a, int b) {
        return a - b; // BUG: should be +
    }
}
EOF

cat > src/test/java/com/example/AppTest.java <<'EOF'
package com.example;

import org.junit.Test;
import static org.junit.Assert.*;

public class AppTest {
    @Test
    public void testAdd() {
        assertEquals(5, App.add(2, 3));
    }
}
EOF

mvn test

Expected: BUILD FAILURE with an assertion error in Surefire output.

Save the log:

mvn test 2>&1 | tee /tmp/java-maven.log

Step 2 — Fix with code-agent run¶

Point -w at the Maven module root — the folder containing pom.xml.

code-agent run \
  "Fix failing AppTest. The add method in App.java returns the wrong result. Run 'mvn test -q' until BUILD SUCCESS. Change only what is needed." \
  --verify-cmd "mvn test -q" \
  -w /tmp/java-demo/demo

Inside the loop¶

1. Agent reads src/main/java/com/example/App.java and the test.
2. Agent patches production code via file tools — not chat-only suggestions.
3. Agent runs mvn test -q.
4. Exit 0 → done. Non-zero → iterate.

No green Maven build, no done. That is the core rule.

On success:

Status: done
Files: src/main/java/com/example/App.java

Verify:

cd /tmp/java-demo/demo && mvn test -q
# BUILD SUCCESS

Flags explained¶

If CI runs mvn verify or ./mvnw test, use that exact command in --verify-cmd.

Step 3 — Fix with bug-fix expert (CI log mode)¶

When Jenkins or GitHub Actions already failed and you have the log:

cd /tmp/java-demo/demo
mvn test 2>&1 | tee /tmp/java-maven.log

code-agent experts run bug-fix \
  --log /tmp/java-maven.log \
  --verify-cmd "mvn test -q" \
  -w /tmp/java-demo/demo

Optional workflow flags:

• --dry-run — plan without pushing
• --publish — commit fix, push branch, open draft PR (gh auth login required)

Gradle — short path¶

Gradle projects follow the same rules with different verify commands.

mkdir -p /tmp/gradle-demo && cd /tmp/gradle-demo
git init

gradle init --type java-application --dsl kotlin \
  --test-framework junit-jupiter --package com.example --project-name demo

cd demo
# Introduce the same a - b bug in your App class, then:
./gradlew test 2>&1 | tee /tmp/java-gradle.log

code-agent experts run bug-fix \
  --log /tmp/java-gradle.log \
  --verify-cmd "./gradlew test" \
  -w /tmp/gradle-demo/demo

Pick one tool per project. Do not mix Maven flags with a Gradle repo.

CI integration pattern¶

mvn test -q 2>&1 | tee /tmp/ci.log

code-agent experts run bug-fix \
  --log /tmp/ci.log \
  --verify-cmd "mvn test -q" \
  -w "$GITHUB_WORKSPACE"

Your pipeline still owns credentials, JDK setup, and artifact caching. The agent owns the edit-until-green loop.

For PRs that keep failing after pushes:

code-agent experts watch \
  --pr 42 \
  --verify-cmd "mvn test -q" \
  -w /path/to/java-project

Common mistakes¶

What you learned¶

• Maven proof = mvn test -q (or your CI's equivalent).
• -w scopes to the module; --verify-cmd scopes success.
• Gradle uses ./gradlew test — same loop, different gate.
• The agent edits with tools and stops only on verify exit 0.

Next: Quick Start · Java examples · Coverage tutorial · Questions: cluevion@gmail.com