Product-only:

Product-only:
- updating an entity doesn't work with a persist() invocation, not at least
  what JPA 2.1 says. As here JPA 2.1 is honored and not a specific
  implementation like Hibernate is, persist() will lead to a double entry.
  You need to use find() + copy all fields + merge() to archive this the proper
  way under JPA 2.1
- updated method invocations due to updated jproduct-core.jar

Signed-off-by: Roland Häder <roland@mxchange.org>