import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.nio.channels.FileChannel;
public class Main {
public static void main(String[] argv) throws Exception {
FileChannel srcChannel = new FileInputStream("srcFilename").getChannel();
FileChannel dstChannel = new FileOutputStream("dstFilename").getChannel();
dstChannel.transferFrom(srcChannel, 0, srcChannel.size());
srcChannel.close();
dstChannel.close();
}
}