This is the wrong conclusion. The conclusion should be that a dedicated server or a VPS hosted by a third party is inappropriate when a very high data security is required and you cannot trust the hosting company, since there is no practical way to prevent access to your data even if you encrypt it, whether you use ObjectDB or any other DBMS.
As explained above, there is no real difference between internal ObjectDB encryption (which is currently not supported) to external file encryption, since in both cases your application is active with the password. An administrator can take a RAM snapshot of your application or your application communication with the database or with the users (before encryption) and get access to your data.
If you cannot trust your hosting company switch to another company or manage your own server, whether you use ObjectDB or not.
ObjectDB - Fast Object Database for Java (JPA/JDO)