UserProvider provider = UserProvider.instantiate(conf);
if (realUserNamePresent) {
String realUserName = in.readUTF();
UserGroupInformation realUserUgi =
UserGroupInformation.createRemoteUser(realUserName);
user = provider.create(
UserGroupInformation.createProxyUser(username, realUserUgi));
} else {
user = provider.create(UserGroupInformation.createRemoteUser(username));
}
} else {