def parameter_value_of(param)
      _String = Rjb::import 'java.lang.String'
      # Using Rjb::import('java.util.HashMap').new, it returns an instance of
      # Rjb::Rjb_JavaProxy, so the Rjb_JavaProxy parent is the Rjb module itself.
      if param.class.parent == Rjb
        param
      else
        _String.new(param.to_s, "UTF-8")
      end
    end
def parameter_value_of(param)
      _String = Rjb::import 'java.lang.String'
      # Using Rjb::import('java.util.HashMap').new, it returns an instance of
      # Rjb::Rjb_JavaProxy, so the Rjb_JavaProxy parent is the Rjb module itself.
      if param.class.parent == Rjb
        param
      else
        _String.new(param.to_s, "UTF-8")
      end
    end
Returns the value without conversion when it's converted to Java Types.
 When isn't a Rjb class, returns a Java String of it.