When I export my game as runnable .jar file with custom window's icon - it doesn't run. It runs only in debug mode and when I try to launch .jar with the console it says that it cannot load icon file.
You probably did not include the icon in your jar file, or you did include it, but not in the right location. From the console, run
jar tf Trace.jar
to get a list of all files that are actually included in your .jar file. Check if there is an entry for the given path, namely
If it is absent you'll have to configure your IDE to include it properly. If the image file is there, but not under the above path, you'll either have to configure your IDE to put it in the correct place inside the jar, or adapt your code to look for the file in a different place.