There is JDBC adapter that will give you flexibility to do all the database DML operations that you want and with all the facilities/framework at your disposal to perform database operations. I think it might not be a good idea to re-invent the wheel again by writing java service and utilize JDK jdbc service to establish the connection and then manipulate the data.
If you want to look for example on Java JDBC service, feel free to google and I’m sure there are so many example out there.
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