The REST server supports request header Key-Content-Type, which changes the meaning of the key in the request URI to be encoded in different media types.

One of the supported media types is application/x-java-object, which parses Java primitives as if they were Java literals, with special handling for String and byte[]. The parsing rules are ad-hoc and undocumented, so I suggest we stop supporting them.

Users who want a readable URI should instead use write the key as JSON and rely on the server to transcode between JSON and the cache storage media type.