Efficient file copy in Java (pre-JDK7)

copyFile

public static void copyFile(File sourceFile, File destFile, final boolean isOverwrite) throws IOException {
  if (destFile.isDirectory())
     destFile = new File(destFile, sourceFile.getName());
  if (destFile.exists())
  {
     if (isOverwrite)
        destFile.delete();
     else
        throw new IOException(destFile.getAbsolutePath() + " exists");
  }
  if (!destFile.exists()) {
    destFile.createNewFile();
  }
  FileInputStream fIn = null;
  FileOutputStream fOut = null;
  FileChannel source = null;
  FileChannel destination = null;
  try {
    fIn = new FileInputStream(sourceFile);
    source = fIn.getChannel();
    fOut = new FileOutputStream(destFile);
    destination = fOut.getChannel();
    long transfered = 0;
    long bytes = source.size();
    while (transfered < bytes) {
      transfered += destination.transferFrom(source, 0, source.size());
      destination.position(transfered);
    }
  } finally {
    if (source != null) {
      source.close();
    } else if (fIn != null) {
      fIn.close();
    }
    if (destination != null) {
      destination.close();
    } else if (fOut != null) {
      fOut.close();
    }
  }
}