How to use environment variables in configuration files

[Gualtiero Testa]

Hi,

I would like to use environment variables to partially change the James
configuration.

My use case it to create a Docker image and use environment variable to
influence some parameters in the config XML files, depending on the
execution environment.

For example I would like to change the "postmaster" address in the
mailet-container.xml file.

Is there a way to do it?

Thanks,

Gualtiero