Changing jar to zip file

[Jay man]

(05-16-2020 01:18 PM)game launcher Wrote:  yeap,that save will be download in a folder as .zip then locate it with screenresizer?after you are done ,open blue ftp and rename to .jar

that is what i did, but it doesn't work. I downloaded it in a folder with operamini in zip format.
How can i locate the original jar file(the game itself in .jar format)?, or is it not possible?
I only saw midlet private. I used royal file explorer and blueftp, both can't locate it