Trasforma EPUB in GIF tramite Java

public static void StoreToDatabase(Document doc, Connection mConnection) throws Exception {
    // create an output stream which uses byte array to save data
    ByteArrayOutputStream aout = new ByteArrayOutputStream();
    // save the document to byte array
    doc.save(aout, SaveFormat.GIF);
    // get the byte array from output steam
    // the byte array now contains the document
    byte[] buffer = aout.toByteArray();
    // get the filename from the document.
    String fileName = doc.getOriginalFileName();
    String filePath = fileName.replace("\\", "\\\\");
    // create the SQL command.
    String commandString = "INSERT INTO Documents (FileName, FileContent) VALUES('" + filePath + "', '" + buffer + "')";
    Statement statement = mConnection.createStatement();
    statement.executeUpdate(commandString);
}