Copy a file with InputStream and OutputStream

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class Main {
  final static int BUFF_SIZE = 5 * 1024 * 1024; // 5MB
  final static byte[] buffer = new byte[BUFF_SIZE];

  public static void main(String[] arg) throws IOException {
    copy(new File("s"), new File("t"));
  }
  public static void copy(File s, File t) throws IOException {
    InputStream in = new FileInputStream(s);
    FileOutputStream out = new FileOutputStream(t);
    while (true) {
      int count = in.read(buffer);
      if (count == -1)
        break;
      out.write(buffer, 0, count);
    }
    out.close();
    in.close();
  }
}