package com.myhadooptest1;
 
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
 
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
 
/**
 * Hello world!
 */
public class App {
    public static void main(final String[] args) throws IOException, URISyntaxException
    {
        final Path path = new Path("hdfs://sandbox-hdp.hortonworks.com:8020/user/root/dmmdir");
        final Configuration conf = new Configuration();
        // conf.set("fs.defaultFS", "hdfs://sandbox-hdp.hortonworks.com:8020");
        final FileSystem fileSystem = FileSystem.get(new URI("hdfs://sandbox-hdp.hortonworks.com:8020"), conf);
 
        if (fileSystem.exists(path)) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
 
        final FileStatus[] fileStatuses = fileSystem.listStatus(path);
 
        for (final FileStatus fileStatus : fileStatuses) {
            System.out.println(fileStatus.getPath().getName());
        }
    }
}

package com.myhadooptest2;
 
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
 
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
 
/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args ) throws IOException, URISyntaxException
    {
        Configuration conf = new Configuration();
        conf.set("fs.defaultFS", "hdfs://sandbox-hdp.hortonworks.com:8020");
        FileSystem fileSystem = FileSystem.get(new URI("hdfs://sandbox-hdp.hortonworks.com:8020"), conf);
        
        Path path = new Path("hdfs://sandbox-hdp.hortonworks.com:8020/user/root/dmmdir/myhadooptest2.txt");
 
        FSDataOutputStream fdostream = fileSystem.create(path);
        fileSystem.setPermission(path, new FsPermission("777"));
 
        fdostream.write("Hello world!".getBytes());
        //fdostream.flush();
        fdostream.close();
        fileSystem.close();
 
        System.out.println( "Hello World!" );
    }
}