require 'java'

import java.util.jar.JarFile;

sys_jar_loc = "/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar"

interfaces = JarFile.new(sys_jar_loc).entries.map do |entry|
  if entry.name.match /java.*\.class$/ and not entry.name.match(/\$/)
    begin
      clas = java.lang.Class.forName(entry.name.gsub(/\.class$/,'').gsub(/\//,'.'))
      clas.isInterface ? clas : nil
    rescue
      nil
    end
  end
end

interfaces.compact.sort_by{|c| -c.methods.size}.take(20).each_with_index do |c, i|
  puts "#{i+1}. #{c.name} - #{c.methods.size} methods"
end