BinaryObject vs a HashMap

[Mikael]

Hi!

Is there some meta data storage overhead for binary object "types" ? I 
need a cache where the value is pretty much a small key value store 
(5-10 keys and values, all strings, every value different) and with that 
few values maybe just two arrays with keys and values or a hash map, but 
as I will read out single values all the time I thought using binary 
objects would be a better choice to avoid deserialization, but all 
objects will be different, so if the cache has 10000 entries all 10000 
might be different "type", would it be a good choice to use a binary 
object as a simple key/value storage or would I be better of using a 
POJO or HashMap ?

What I don't get is if there is some meta data stored behind the scenes 
for each different type of binary object I create or if it's fine to 
have all binary objects in a cache all being different.

Mikael