So finally I found the solution how to solve my problem (pretty easy with the help of @Ingo_Richtsmeier ´s link):
With this link camunda-7-code-examples/snippets/springboot-customized-webapps at main · camunda-consulting/camunda-7-code-examples · GitHub you can learn, how to create the springboot-customized-webapp-webjar.
After this, you can follow this link https://github.com/camunda/camunda-bpm-examples/tree/master/cockpit/cockpit-sample-plugin to add a custom plugin to your project.
If you put the pieces together, you just have to add under the pom.xml in the springboot-customized-webapp-webjar following line:
<dependency> <groupId>org.camunda.bpm.cockpit.plugin</groupId> <artifactId>cockpit-sample-plugin</artifactId> <version>1.0-SNAPSHOT</version> <scope>runtime</scope> </dependency>
After this you should see the plugin in the cockpit section, when you run the springboot-customized-webapp-example.
Kind regards,
Marvin