Your class btnSaveListener must be in a file named
btnSaveListener.java in the directory guestList (because that's the name of the pacakge that the class is in). It will not work if you put this in a file named gList.java.
The name of the file must always be the same as the name of the public class that is in the file.
You should also put the base directory that contains the package directory in the classpath, so you should put "L:\My Projects\MyJavaApps" in the classpath, not "L:\My Projects\MyJavaApps\guestList".