.使用 mac 系统，appium 1.4.8 版本，连接安卓真机进行调试
2.测试一个 app，之前可以识别到该界面中的控件信息，现在无法识别，总是报错
下面是错误代码：

info: --> GET /wd/hub/session/1d7b6f31-74f0-4e72-b365-7608f39eea43/source {}

info: [debug] Pushing command to appium work queue: ["source",{}]
info: [debug] [BOOTSTRAP] [debug] Got data from client: {"cmd":"action","action":"source","params":{}}
info: [debug] [BOOTSTRAP] [debug] Got command of type ACTION
info: [debug] [BOOTSTRAP] [debug] Got command action: source

info: [debug] [BOOTSTRAP] [debug] Command returned error:java.lang.RuntimeException: Failed to Dump Window Hierarchy

info: [debug] Responding to client with error: {"status":13,"value":{"message":"An unknown server-side error occurred while processing the command.","origValue":"Failed to Dump Window Hierarchy"},"sessionId":"1d7b6f31-74f0-4e72-b365-7608f39eea43"}

info: <-- GET /wd/hub/session/1d7b6f31-74f0-4e72-b365-7608f39eea43/source 500 93.818 ms - 200
info: [debug] [BOOTSTRAP] [debug] Returning result: {"status":13,"value":"Failed to Dump Window Hierarchy"}