code: public void put(String name, Object value) {
  		Params.notNullOrEmpty(name, "Variable name");
  		Params.notNull(value, "Variable %s value", name);
  		variables.put(name, ConverterRegistry.getConverter().asString(value));
  	}
docs: Set variables value. If variable name already exists its value is overridden. Convert variable value to string before
  storing to variables map. Null is not accepted for either variable name or its value.
  <p>
  This method uses {@link Converter} to convert variable value to string. If there is no converter able to handle given
  variable value type this method rise exception.
  
  @param name variable name,
  @param value variable value.
  @throws IllegalArgumentException if variable name is null or empty or value is null.
  @throws ConverterException if there is no converter able to handle given value type.