What is the best way to migrate bpmn files to Java

Project uses Jbpm processes to handle flows.I am facing below problems while development:

• Most of codes embedded to bpmn script tasks which there is no good IDE support for them, code is not readable,maintainable and etc.
• Merging bpmn files is painful if more than one developer did some changes for same bpmn files
• IDEs doesn't support code debugging for bpms(Only i can see there is Drools setup which only applicable for bpmns on Eclipse IDE, not sure end-to-end debugging will be possible)

My question is what is the best way to migrate BPMN files to Java ?