http://my.oschina.net/u/617085/blog/71740
"Failed to set permissions of path"问题
参考文献：https://issues.apache.org/jira/browse/HADOOP-8089
错误信息如下：
ERROR security.UserGroupInformation: PriviledgedActionException as: hadoop cause:java.io.IOException Failed to set permissions of path:usrhadoop mpmapredstaginghadoop753422487.staging to 0700 Exception in thread "main" java.io.IOException: Failed to set permissions of path: usrhadoop mp mapredstaginghadoop753422487.staging to 0700
解决方法：
Configuration conf = new Configuration();
conf.set("mapred.job.tracker", "[server]:9001");
"[server]:9001"中的"[server]"为Hadoop集群Master的IP地址。