When creating a new Maven project using Spring Initializr, you can select Groovy as the project language:

The project gets created with a Groovy application for the main class:

However the generated application is not recognized correctly as a Spring Boot application in the Spring Boot Dashboard:

And the application does not run:

However, let's generate a Java application instead of a Groovy application:

The Java application shows up in the Spring Boot Dashboard:

And it runs just fine:

Spring Initializr should not support creating a Groovy application if it does not work.