## The Code


Object.constants.each do |str|
	obj = Object.const_get(str)
	puts "Class #{obj.name}" if obj.is_a?(Class)
	puts "Class Variables #{obj.class_variables}" if obj.class_variables.empty?
end

## The Error

johnny@johnny-laptop:~/www/why/offbeatenpath$ ruby class_variables.rb
Class ThreadError
Class Variables
Class Numeric
Class Variables
class_variables.rb:8: undefined method `class_variables' for "ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux]":String (NoMethodError)
	from class_variables.rb:5:in `each'
	from class_variables.rb:5