Java.nio.channels.NonWritableChannelException

Question

i have been facing this exception, please tell me how to remove it
java.nio.channels.NonWritableChannelException
here is my code
import java.io.*;
import java.nio.*;
import java.nio.channels.*;
public class abc
     public static void main(String arg[])
          try
          File ff=new File("aaa.txt");
          FileInputStream fis=new FileInputStream(ff);
          FileChannel fc=fis.getChannel();
          FileLock lock=fc.lock();
          lock.release();
          fc.close();
          catch(Exception e)
               System.out.println("hello22"+e);
}

Answer 1

what should i do then to make the channel writable . please tell me what to change in the code, i just want to lock the file and after that i will modify it.