Я использую JPA 2.0.(EclipseLink 2.0.2)
Если сущность содержит отношения, например:
@OneToMany(cascade = CascadeType.ALL, mappedBy = "userId")
private Collection<Blog> blogCollection;
При отправке через RPC появляется следующая ошибка:
com.google.gwt.user.client.rpc.SerializationException: Type 'org.eclipse.persistence.indirection.IndirectList' was not included in the set of types which can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.: instance = {[]}