public String getExpression() {
        return (String) getInput().get(EXPRESSION_PARAMETER);
    }
Javascript tasks are executed on the Conductor server without having to write worker code

<p>Use {@link Javascript#validate()} method to validate the javascript to ensure the script
is valid.

@param taskReferenceName
@param stream stream to load the script file from
java-sdk/src/main/java/com/netflix/conductor/sdk/workflow/def/tasks/Javascript.java