Is there a way to append data to an existing file?

I've tried to use the PrintWriter and CreateWriter, but every time it will create a new file that overwrites the old file..

I've seen people using the FileWriter and setting it true to append the data instead of creating a new file and fill it with data.

But if i use FileWriter, processing says it cant find the class. Is it because of Processing 2+? and is there an other way to use it?

Thank u.

Mike