I apologize if I missed it.
Is it possible to encrypt a wallet in a Java wallet?
None of the Z-fork coins have encryption in the swing wallets. It is a bug that was carried over from zerocoin implementation.
The upcoming ZelTreZ platform has encryption by default for all implemented coins in the wallet, stored completely locally on your machine so no information is stored on Zel servers. Its meant to enhance security for the z-fork coins that are implemented in ZelTreZ.