Every XML document we work on should be formatted correctly, saved with the right encoding, etc.
A classic case is the message “Content is not allowed in prolog” (SAXParseException).
You could edit the file by hand with a (hexadecimal) editor and remove “ef bb bf” at the top.
However, since we are using Java, it is much better to use a small workaround of just two lines of code:
Matcher matcher = (Pattern.compile("^([\\W]+)<")).matcher(xmlString.trim());
xmlString = matcher.replaceFirst("<");
This is before passing it to our SAXBuilder object.
SAXBuilder builder = new SAXBuilder();
Document document = builder.build(new StringReader(xmlString));