private static FileSystem createFileSystem(URI uri, Configuration conf

      ) throws IOException {

    Class<?> clazz = conf.getClass("fs." + uri.getScheme() + ".impl", null);

    if (clazz == null) {

      throw new IOException("No FileSystem for scheme: " + uri.getScheme());

    }

    FileSystem fs = (FileSystem)ReflectionUtils.newInstance(clazz, conf);

    fs.initialize(uri, conf);

    return fs;

  }

<property>

<name>fs.hdfs.impl</name>

<value>org.apache.hadoop.hdfs.DistributedFileSystem</value>

<description>The FileSystem for hdfs: uris.</description>

</property>

configuration.set("fs.hdfs.impl", "org.apache.hadoop.hdfs.DistributedFileSystem");