Server caches without encoding assumes "unknown" format and conversions from/to MediaType.APPLICATION_OBJECT are incorrect: instead of always using the user marshaller to go from/to the storage format, it uses an arbitrary rule where byte[] are stored "as is", String are stored as UTF-8 byte[] and custom objects are marshalled. This causes loss of information when trying to read the stored content.

Many tests are incorrect and take advantage of this wrong conversion