I just made a jar file from an application/applet(it can be run either way) that I wrote. I followed all of the directions on the tutorial in cjards signature. The class that runs my program is called Runner, so in my manifest file I put Main-Class: Runner and then I pressed enter. I typed in jar cvfm SPX.jar mf.txt Saterasoft/ and it made the jar file. When I double click on the jar file, a pop up window informs me that the Main Class cannot be found. Does anyone know why this is happening?