Example of DataInputStream and DataOutputStream.

import java.io.*;

class DataStream
{
public static void main(String surat[]) throws IOException
{
DataInputStream din=new DataInputStream(System.in);

FileOutputStream fout=new FileOutputStream("Mahi.txt");

DataOutputStream dout=new DataOutputStream(fout);

String s="";
while(!s.equals("stop"))
{
s=din.readLine();
System.out.println(s);
dout.writeBytes(s);
dout.flush();
}
din.close();
dout.close();
}
}

Output: