I must admit that I am quite lazy (and not a very tidy person either). When I am given a new database connection to work with, I configure it in SQL Developer and save the password (so I do not have to type it when I connect and, more important, I do not have to remember it or store it safely somewhere else - shame on me!). As a consequence, when I am ask to provide the password to somebody else, it happens quite often that I do not remember it.
SQL Developer stores the saved passwords in an encrypted fashion in a file called connections.xml, which is normally available in \AppData\Roaming\SQL Developer\system folder.
Googling around, I have found a number of Java routines that can decrypt the passwords, but why spending time in compiling some Java code if a solution is already available?
This link http://show-me-password.tomecode.com has the instructions for installing a simple SQL Developer extension. It works great and it's the perfect shortcut for a lazy and forgetful programmer.