=> "2014-04-29T14:21:14.988-07:00", "logger" => "com.example.LogStashExampleTest", "level" => "ERROR", "thread" => "Test worker", "message" => "Something bad happened!", "Properties" => { "loginId" => "John Doe" } } ThreadContext.put("loginId", login); logger.error("Something bad happened!"); ThreadContext.clear(); + JSON Layout Log: