And just to clear up any misinformation you may have read, if one where to just right click the jar file and select "Open with" in the pop-up menu and then select OpenJDK Java runtime it will not run the jar file. At least not if you are running Ubuntu-based Mint and that's the section of the forum we are posting. Instead you will get the following error message:
This forces the user to make the jar file executable. The purists in the crowd will look at that error message and wonder since when do jar files need to have a Linux executable bit set to run? Jar files in and of themselves are not an executable entity they are Java Archives.
BLOCKED: The file '/home/tester1/Downloads/WordBiz/wordbiz.jar' is not marked as executable. If this was downloaded or copied from an untrusted source, it may be dangerous to run. For more details, read about the executable bit.
So there are multiple ways around this issue:
 You can succumb to the convoluted logic of our Ubuntu overlords and actually make the file executable but you still have to use the "open with" procedure. If the jar file sits on a ntfs formatted usb stick or a CDROM well you're out of luck so you will just have to copy it to a linux partition, make it executable , and then use open with.
 You can fix it at it's source by editing the /usr/share/applications/openjdk-7-java.desktop, find the following line, and delete the "cautious-launcher %f" part:
Exec=cautious-launcher %f /usr/bin/java -jar
That removes the need for it being executable but it's not the best of solutions since any update to java will likely rewrite that file. And you still have to use "Open with" to run it.
 You can do what I suggested which does 2 things:
** It bypasses the "cautious-launcher" logic so that the file does not have to be executable and then it can be run from anywhere.
** It sets the jar file association to java so that you can double click it just line on Windows or OSX.
 Or you can do what the developer of the application stated and run the jar from the terminal ( java -jar wordbiz.jar ) which also bypasses cautious-launcher and hence does not require you to make the file executable. That procedure will work just as stated in just about any OS or any DE which is why the developer likely suggested it.