Question

I have a very simple HelloWorld code in Java which works ok. I’m using Eclipse and trying to figure out how to import dependencies for a project with the maven2 eclipse plugin.

    public class testMavenDep {

        public static void main(String arg[]){
            System.out.println("Hello World");
        }
    }

However, when I right click on the project > configure > convert to maven project, and then try and run it gives me an error message saying…

Could not find the main class: testMavenDep.testMavenDep. Program will exit.

And the following in the console…

java.lang.NoClassDefFoundError: testMavenDep/testMavenDep
Caused by: java.lang.ClassNotFoundException: testMavenDep.testMavenDep
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Exception in thread “main”

My pom file is…

<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>testMavenDep</groupId>
  <artifactId>testMavenDep</artifactId>
  <version>0.0.1-SNAPSHOT</version>
</project>

My question is, for an already existing Java Project, what is the proper way to add maven dependencies? I can add the dependencies using the above method but I’m getting issues with it losing track of the main class. Thanks in advance!

Answer 1

What is the source folder that you are putting your main class in? By default, Eclipse puts it in src, but maven conventions are src/main/java. It could be that adding maven dependencies is changing your source folders so that your class is not compiled.