I keep trying to run a.jar file but it always unzips it?

I'm a bit of a noobie pc gamer and i'm trying to install mods for minecraft for the first time. Whenever i try to run forge it unzips it instead of running the installer, any body know why?

A.jar file is a zipped file.

Do you have java updated to the latest version? If not then upgrade java, that is very important. Also, do you have WinRAR or 7-Zip? If you do, these programs are setup by default to open.jar files instead of running them. Try this, right click on the forge installer.jar file, open with, then click java se binary (or something along these lines)

No actual MIME entry that links.jar to running java.exe I amj not aware of one that does that.

.jar is using exact same framework as a.zip and a Zip suite must have MIME entry that links.jar to uncompression.

You can still do it manually according to instruction of java.exe MIME is a simple GUI double-clicky trick.