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🏗️ 1. Ensure Your GitLab Project Is Maven-Ready

To store your Java packages (JAR/WAR) into the GitLab Package Registry using GitLab CI/CD (SaaS, version 18.x), you can use GitLab’s built-in Maven repository support.

Here’s a step-by-step guide to:

✅ Build your Java project
✅ Upload the .jar or .war to GitLab’s Maven Package Registry
✅ Do this all through your .gitlab-ci.yml pipeline

In your project root:

Ensure pom.xml (for Maven) is set up with:

<project>
  ...
  <groupId>com.example</groupId>
  <artifactId>my-app</artifactId>
  <version>1.0.0</version>
  ...
</project>
Code language: HTML, XML (xml)

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🧪 2. GitLab Package Registry URL

GitLab SaaS Maven registry endpoint:

https://gitlab.com/api/v4/projects/<PROJECT_ID>/packages/maven
Code language: HTML, XML (xml)

You can find <PROJECT_ID> in your GitLab project settings or by using:

https://gitlab.com/<namespace>/<project_name>
Code language: HTML, XML (xml)

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🔐 3. Create a CI/CD Job to Publish Artifact

.gitlab-ci.yml example for Maven:

stages:
  - build
  - publish

variables:
  MAVEN_CLI_OPTS: "-B -DskipTests"

build-job:
  stage: build
  image: maven:3.8.7-jdk-11
  script:
    - mvn $MAVEN_CLI_OPTS clean package
  artifacts:
    paths:
      - target/*.jar
      - target/*.war

publish-job:
  stage: publish
  image: maven:3.8.7-jdk-11
  script:
    - mvn deploy -s settings.xml
  only:
    - main
Code language: PHP (php)

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⚙️ 4. Add settings.xml for GitLab Auth

In the root of your repo (or dynamically generate in CI):

<settings>
  <servers>
    <server>
      <id>gitlab</id>
      <username>gitlab-ci-token</username>
      <password>${env.CI_JOB_TOKEN}</password>
    </server>
  </servers>
</settings>
Code language: HTML, XML (xml)

Ensure your pom.xml contains:

<distributionManagement>
  <repository>
    <id>gitlab</id>
    <url>https://gitlab.com/api/v4/projects/<PROJECT_ID>/packages/maven</url>
  </repository>
</distributionManagement>
Code language: HTML, XML (xml)

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🛡️ 5. Use the CI_JOB_TOKEN Securely

• gitlab-ci-token is a special user recognized by GitLab’s package registry.
• CI_JOB_TOKEN is auto-injected in GitLab CI/CD and scoped to your project.

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📦 6. Check Published Packages

After the pipeline completes:

1. Go to your GitLab project
2. Click on Packages & Registries → Package Registry
3. You’ll see your .jar or .war listed

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🧠 Bonus: Clean Up or Promote Packages

You can add manual jobs to:

• Promote packages to another environment
• Delete old versions via API
• Install them in another Java project using Maven:

<dependency>
  <groupId>com.example</groupId>
  <artifactId>my-app</artifactId>
  <version>1.0.0</version>
</dependency>
Code language: HTML, XML (xml)

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✅ Summary

Step	Description
Build Artifact	Use mvn package in CI job
Upload to GitLab	Use mvn deploy with GitLab Maven repo
Auth	Use CI_JOB_TOKEN with gitlab-ci-token
View	Packages tab in GitLab UI

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How to use Package registry using Gradle

Here is a step-by-step guide to publish JAR/WAR packages from a Gradle-based Java project to GitLab’s Maven Package Registry, using GitLab SaaS 18.x.

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✅ Overview

• You’ll use GitLab’s Maven-compatible Package Registry
• You’ll configure Gradle to use GitLab as a Maven repo
• You’ll automate it using .gitlab-ci.yml and CI_JOB_TOKEN

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📁 1. Setup Your Gradle Project

In your build.gradle file:

plugins {
    id 'java'
    id 'maven-publish'
}

group = 'com.example'
version = '1.0.0'

publishing {
    publications {
        mavenJava(MavenPublication) {
            from components.java
        }
    }
    repositories {
        maven {
            name = "GitLab"
            url = uri("https://gitlab.com/api/v4/projects/<PROJECT_ID>/packages/maven")
            credentials {
                username = project.findProperty("gitlabUser") ?: System.getenv("CI_JOB_TOKEN")
                password = project.findProperty("gitlabToken") ?: System.getenv("CI_JOB_TOKEN")
            }
        }
    }
}
Code language: JavaScript (javascript)

Replace <PROJECT_ID> with your GitLab project ID. You can find it on the project homepage (e.g., gitlab.com/api/v4/projects/1234567).

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🔐 2. No Hardcoded Credentials

Do not store username/token in code.

In CI/CD, GitLab will inject CI_JOB_TOKEN automatically. For local testing, you can override via gradle.properties or CLI:

gitlabUser=gitlab-ci-token
gitlabToken=<your personal access token>
Code language: HTML, XML (xml)

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🧪 3. Test Locally (Optional)

./gradlew publish \
  -PgitlabUser=gitlab-ci-token \
  -PgitlabToken=<your GitLab personal access token>
Code language: HTML, XML (xml)

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⚙️ 4. Create .gitlab-ci.yml

stages:
  - build
  - publish

variables:
  GRADLE_USER_HOME: "$CI_PROJECT_DIR/.gradle"

build-job:
  stage: build
  image: gradle:8.2.1-jdk17
  script:
    - gradle build

publish-job:
  stage: publish
  image: gradle:8.2.1-jdk17
  script:
    - gradle publish
  only:
    - main
Code language: JavaScript (javascript)

This will publish the JAR/WAR file to GitLab Package Registry on main branch only.

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📦 5. Where to View Packages

After successful pipeline execution:

• Navigate to Your Project → Packages & Registries → Package Registry
• You’ll see the .jar or .war under your published Maven group.

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🔁 6. How to Use in Other Projects

In another Gradle project, consume the published package:

repositories {
    maven {
        url = uri("https://gitlab.com/api/v4/projects/<PROJECT_ID>/packages/maven")
        credentials {
            username = 'gitlab-ci-token'
            password = System.getenv("CI_JOB_TOKEN") // or use .env or gradle.properties
        }
    }
}

dependencies {
    implementation 'com.example:your-artifact:1.0.0'
}
Code language: JavaScript (javascript)

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✅ Summary Table

Step	Action
build.gradle	Add maven-publish, configure GitLab Maven repo
Credentials	Use CI_JOB_TOKEN with gitlab-ci-token
.gitlab-ci.yml	Run gradle publish from CI/CD
Registry URL	https://gitlab.com/api/v4/projects/<PROJECT_ID>/packages/maven
View Packages	Project → Packages & Registries → Package Registry

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