public class FileReaderMiniJava extends MiniJava{
    // reads a file as string
    public static String readFile(String filename) {
        try {
            // initialization
            java.io.BufferedReader reader = 
                new java.io.BufferedReader(new java.io.FileReader(filename));
            StringBuffer buffer = new StringBuffer();

            // read line after line
            String line;
            while ((line = reader.readLine()) != null)
                buffer.append(line);
            reader.close();

            // return file contents as string
            return buffer.toString();

        } catch (Exception e) {
            // error handling
            System.err.println(e);
            return null;
        }
    }
}