Java NIO file ops

CopyFile.java

import java.io.FileInputStream;
import java.io.FileOutputStream;

public class CopyFile {
  
  public static void main(String[] args) {
    String infname = "/tmp/in.txt";
    String outfname = "/tmp/out.txt";
    FileInputStream fis = new FileInputStream(infname);
    FileOutputStream fos = new FileOutputStream(outfname);
    FileChannel fcin = fis.getChannel();
    FileChannel fcout = fos.getChannel();
    ByteBuffer buff = ByteBuffer.allocate(1024);
    while(true) {
      // read mode(from channel to buffer);
      // set position to 0, limit to capacity;
      buff.clear();
      int n = fcin.read(buff);
      if (n == -1) {
        break;
      } else {
        // write mode(from buffer to channel);
        // set limit to position, position to 0;
        buff.flip();
        fcout.write(buff);
      }
    }
  }
  
}