String replace using huge heap space

Question

I am doing a xml parsing and doing some string replaceAll which is using a huge amount of memory space as shown in the below image.

Code goes like:

private final String getText() {
  // special handling for apostrophe encoding
  // site will expect both ' , ' and %27.
  // change %27 or 'or ' to '
  return _text.toString().trim().replaceAll("'", "'")
            .replaceAll("'", "'").replaceAll("%27", "'");
}

The getText() method is frequently call from endElement() method of SAXParser.

Can anyone suggest how do change this functionality which will use lesser heap space

![trace][1]

Answer 1

Use replace() instead of replaceAll(). replaceAll() uses regular expression and you don't need them plus they are overhead.

Answer 2

Using regular expressions for simple string replacement like this is too expensive. I would simply build a StringBuilder instance like this:

StringBuilder sb = new StringBuilder();

while (not end of _text) {
   find next '&'
   if the next substring is in (' ') etc.
     append the prev portion of _text to sb
     append replacement char
     set the beginning of the chunk to the next char
}
return sb.toString();