This is how a single source file should look like:

• UTF-8 encoding:
  All source files should be encoded in UTF-8.
• optional Header:
  A comment holding author, copyrights, etc.
• optional Compiler Hints:
  Can be any number of the following (Note: Those compiler hints have to start in the first column!):
  • #use(classpattern) – other class that has to be added to the application
  • #require(classpattern) – other class that has to be added to the application before this class
  • #asset(resourcepattern) – resources that are used by this class (required if the class uses resources)
• a single Definition:
  One call to a define() method, such as qx.(Class|Theme|Interface|Mixin|...).define().

Example:

/* ************************************************************************
 
   Copyright:
 
   License:
 
   Authors:
 
************************************************************************ */
 
/* ************************************************************************
 
#require(qx.core.Assert)
#use(qx.log.Logger)
#asset(custom/*)
 
************************************************************************ */
 
qx.Class.define("custom.Application",
{
  ...
});