If you play around with Java on your Windows box, sooner or later you are going to hit the problem where you need to create a file that starts with a period (aka. dot or full stop) e.g. “.keypass”.
Explorer won’t let you do this.
The solution is to create a file called keypass (no period) in Explorer and then use the command prompt to run a DOS command:
ren keypass .keypass
“ren” = “rename”
Good, old DOS to the rescue!