You need to take over serialization of your class.

Instead of
ObjectOutputStream.writeObject(connection);

do

ObjectOutputStream.writeObject(informationToGetConnection);

and instead of
ObjectInputStream.readObject(connection);
do

ObjectInputStream.readObject(informationToGetConnection);
connection = getConnection(informationToGetConnection);

Be careful with where your object is transferred to.

If it goes over a network and you put a password
in the stream somebody can sniff it,
it probably won't be encrypted.
Regards,
Adrian