global

def require_jar(*args, &block)
  return nil unless Jars.require?

  result = Jars.require_jar(*args, &block)
  if result.is_a? String
    args << (yield || Jars::UNKNOWN) if args.size == 2 && block
    Jars.warn do
      "--- jar coordinate #{args[0..-2].join(':')} already loaded with version #{result} - omit version #{args[-1]}"
    end
    Jars.debug { "    try to load from #{caller.join("\n\t")}" }
    return false
  end
  Jars.debug { "    register #{args.inspect} - #{result == true}" }
  result
end