Password Cracking

hello guys, i really need help. i recently managed to hack into a java aplications database and passwords were encrypted in this way . " 54CE5EBE53B874","3f 757D145C75FA4A4A36BA667A57A" to mention but a few. after along google searching, i realised these java applications use keys to encrypt passwords. i even downloaded the full system on my pc but dont know how to find the encryption keys. can some one help?? help will be apreciated