I have partially found the cause of my problem.
On the server, my EJB Entities are stored using JPA (TopLink). So there are JPA annotations in my entities.
Instead of sending directly my entities to the client, I tried to "copy" my entities into POJO objects (without annotations). The result is impressive : before the serialization took 3.6 MB and now it takes only 50 KB.
In the attached files, you can see a piece of the dump for both cases.
My question now : Is it possible to serialize Entites without the annotations ?
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