使用httpclient代理警告的含义是什么？

Question

我想在程序中使用代理作为流程：

HttpClient httpClient = new HttpClient();  
httpClient.getHostConfiguration().setProxy("192.168.0.1", 9527);  
httpClient.getParams().setAuthenticationPreemptive(true);

但是日食总是输出：

WARNING: Required proxy credentials not available for BASIC <any realm>@192.168.0.1:9527
WARNING: Preemptive authentication requested but no default proxy credentials available
WARNING: Required credentials not available for BASIC <any realm>@www.google.com:80
WARNING: Preemptive authentication requested but no default credentials available

为什么？你能帮助我吗 ？感谢。