i have the situation that i have two running java processes with each an activiti engine on the same database. They have the same configuration so both have activated the JobExecutor. I don't test it yet, but will i get problems? Is it better to ensure that only one engine has an activated JobExecutor?
It's fine to have multiple job executors. You only have to be aware that every Activiti Engine needs to have the Java classes attached to each process definition on the classpath.