Is there a listener or program that can be used to sync across data from/to MySQL and ObjectDB so that I can use ObjectDB for development and then just make sure MySQL always has the same data?
Sync ObjectDB and MySQL
There are plans to implement such a tool. You may subscribe to this feature request if you are interested. But currently this is not supported yet, and it is unclear yet when it will be implemented.
You may try wrapping operations against ObjectDB in a database access layer code that will execute these database operations on both ObjectDB and MySQL (accessing MySQL using another JPA implementation).
ObjectDB - Fast Object Database for Java (JPA/JDO)