I am a newbie to Flowable 6, when I call Context.getCommandContext(), in some cases it return a null object.
My question is that which conditions are needed to have a command context?. And in my case, if it is null, can I manually add one. If yes, how to do it?
The Context API is an internal Flowable API and users are advised not to use that API.
You should not manually add a context, that is handled by the Flowable command context execution.
When invoking your logic in a Command then the Context.getCommandContext() will not be null.
What I would suggest is to do something like:
managementService.executeCommand(commandContext -> {
// Do something with the commandContext here
}