This tutorial describes the usage of Maven within the Eclipse IDE for building Java applications.
1. Using Maven with the Eclipse IDE
The Eclipse IDE supports Maven via the M2Eclipse (m2e) project. m2e provides an editor for the pom.xml file, downloads dependencies and manages the classpath of your projects. Wizards allow you to import existing Maven projects and to create new ones. == Installation and configuration of Maven for Eclipse
1.1. Installing the Maven tooling
The Eclipse IDE for Java Developers already includes Maven support. To check, select and look for the m2e logo.
Installing Maven support
Select and enter the following update site in the Work with field.
https://download.eclipse.org/releases/latestFor Java projects, you only need the m2e component.
1.2. Updating the project configuration automatically
Eclipse updates the project configuration automatically after you change the pom.xml file. The Automatically update Maven projects configuration setting under controls this.
2. Exercise: Create a Maven project
In this exercise, you create a Maven project with the Eclipse IDE.
2.1. Create the project
Select .
The first page allows you to create a simple project without an archetype. In this exercise, you use an archetype as template, so leave Create a simple project unchecked and press Next.
Filter for maven-archetype-quickstart and select the entry with the org.apache.maven.archetypes group.
On the last page, enter com.vogella as Group Id and com.vogella.maven.eclipse as Artifact Id and Package.
Clear run archetype generation interactively and press Finish.
The archetype creates an App class, a JUnit 5 test and a pom.xml file.
2.2. Set the Java version
The generated pom.xml file compiles for Java 17.
Open it, switch to the pom.xml tab of the editor and change the maven.compiler.release property to 25.
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.release>25</maven.compiler.release>
</properties>2.3. Update the project configuration
Eclipse updates the project configuration when you save the pom.xml file. To trigger an update manually, right-click the project and select .
2.4. Validate
Right-click the project and select .
Enter clean verify in the Goals field and press Run.
The build succeeds.
3. Exercise: Use an external library
In this exercise, you add the Gson library to the project of the previous exercise.
3.1. Add a dependency
You can add a dependency directly in the pom.xml file or via the Dependencies tab of the pom editor. Switch to the Dependencies tab and press Add….
Enter com.google.code.gson as Group Id, gson as Artifact Id and 2.15.0 as Version.
You find the latest version on Maven Central.
Save the pom.xml file, Eclipse updates the project and downloads the library.
3.2. Use the library
Create or change the App class in the src/main/java folder.
package com.vogella.maven.eclipse;
import com.google.gson.Gson;
public class App {
public static void main(String[] args) {
Gson gson = new Gson();
System.out.println(gson.toJson("Hello World!"));
}
}The class compiles, as Maven added Gson to the classpath. Right-click it and select .
3.3. Validate
Run the Maven build again with clean verify.
The build succeeds.
4. Exercise: Converting a Java project (create with Eclipse) to Maven
This exercise demonstrates how to convert a Java project to a Maven project.
4.1. Create Java project
Create a new Java project called com.vogella.build.maven.simple in Eclipse.
Add one class called Main.
This class should have a main method, which write "Hello Maven!" to the command line.
package com.vogella.build.maven.simple;
public class Main {
public static void main(String[] args) {
System.out.println("Hello Maven!");
}
}4.2. Convert to Maven project
Select your project, right-click on it and select .
This creates a pom.xml file similar to the following.
<project
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.vogella.build.maven.simple</groupId>
<artifactId>com.vogella.build.maven.simple</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>4.3. Execute the Maven build
Right-click the pom.xml file and select .
Enter "clean install" as Goal.
| You have to enter the goals manually. The Select… button does not work, the dialog it displays is always empty. |
Press the Finish button. This starts the build, which you can follow in the Console view.
Once the build finishes, press F5 on the project to refresh it. You see a target folder that contains the build artifacts, e.g., a JAR file.
5. Exercise: Create a Java web project in Eclipse using Maven
This exercise demonstrates how to create a web application in Eclipse that uses Maven. It assumes that you have already configured Eclipse for the creation of web applications.
5.1. Create a Maven web project
Create a new Maven project called com.vogella.javaweb.maven.first via the entry. On the archetype selection, select the maven-archetype-webapp entry and click the Next button.
Enter the group, artifact and version of your new Maven component.
|
You may see the error: The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path. To fix this, right-click on your project and select Properties. On the Targeted Runtimes select your web server entry, e.g., Tomcat. |
5.2. Build your project
Run your mvn clean verify build command from Eclipse.
Validate that there are no issues with the build.
5.3. Run on the server
Right-click your project and select the menu entry.
If you open a browser you should be able to access your webapplication.
6. Exercise: Debug tests of a Maven build
Set a breakpoint in one of your tests.
Start the Maven build on the command line with the following command.
mvn -Dmaven.surefire.debug testBefore running the tests, the build waits for a debugger on port 5005.
In Eclipse, select and create a Remote Java Application configuration.
Select your project, enter port 5005 and press Debug. Eclipse connects to the build and stops at your breakpoint. == References for Webdevelopment with Eclipse
To use Maven in Eclipse for Java web development, you should install an configure the Eclipse web development tools (WTP). See Eclipse Web Development Tools for a tutorial.
7. Eclipse Maven (m2e) resources
7.1. vogella Java example code
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