Run the docker image with  docker run -p 8080:8080 -p 8001:8001 -d --name jbpm-server-full jboss/jbpm-server-full:latest Browse to http://localhost:8080/business-central  and login with wbadmin account  Navigate to Admin -> Custom Tasks Administration Upload a jar that contains a sample workitemhandler e.g. you can use this code to generate a sample project:  mvn archetype:generate -DarchetypeGroupId=org.jbpm -DarchetypeArtifactId=jbpm-workitems-archetype -DarchetypeVersion=7.42.0.Final -DgroupId=org.jbpm.contrib -DartifactId=custom-workitem -DclassPrefix=Custom -Dversion=7.42.0-SNAPSHOT -DarchetypeCatalog=local Check the status text on the message on top of the screen (see attachment Upload_1.png): this contains a the string "/n" and shows a message that does'nt make sense as I uploaded the jar with the workitemhandler the first time.  Try to upload the same jar again I get the same message on top of the screen. Now this makes sense but has the unwanted string "/n" also included (see attachment Upload_2.png).