Spring boot and maven exec plugin issue

Question

I\'ve created a bare-bone Maven project, completely empty except the pom.xml.

With this pom (note that parent element is commented-out):

Answer 1

Its because Spring-Boot is adding some extra maven configuration to your project. If you are using eclipse, there's a Tab called: 'Effective POM'.

From this tab you can see that it adds this snippet below:

    
      org.codehaus.mojo
      exec-maven-plugin
      1.2.1
      
        ${start-class}
      
    

So when you run it with spring-boot as parent, it looks for the value of ${start-class}, which resolves to empty unless you defined it, that's when you see the error about not having a value for the mainClass parameter.

Add this to your project:

    com.Test

Then run it: clean compile exec:java

[INFO] --- exec-maven-plugin:1.2.1:java (default-cli) @ springboot-test ---
**********test**************
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.388 s
[INFO] Finished at: 2014-12-05T15:25:05-06:00
[INFO] Final Memory: 17M/231M
[INFO] ------------------------------------------------------------------------

You can also provide the value for the start-class property on the command line, this works even if you didn't define it inside your pom file:

mvn exec:java -Dstart-class=com.Test