Well it looks like WmDB was deprecated in favor of JDBC adapter, but as reamon points out the removal of this package due legacy code was a big issue for many people already using it, and was placed back as “regular”.
The IS built-in services guide states:
Answer is yes, JDBC adapter also provides you services to be used in your code.
If you are starting a new development this should be enough reason for not using WmDB and use JDBC adapter ones instead.
#Integration-Server-and-ESB#webMethods#Flow-and-Java-services