What you mean by 'usi in your own app'?
If you place the app in the deploy directory you can enable hotdeployment (for default and all configuration it should be enabled).
All *-ds.xml and EAR/WAR etc. will be checked and hot-deployed if added, removed or changed.
If you mean other config files placed everywhere there is no standard mechanism (AFAIK) you have to implement by yourself.
But it might not a good idea in general because the JEE spec does not allow to access files.
Thx for the reply.
It doesn't have to be a standard JEE mechanism
And indeed, *-ds.xml is another example of a hot-deployable/hot-editable config file.
I understand that this is not in line with JEE philisophy in general.