I'm not sure what the problem is, exactly. I do ArrayLists like this, and it works fine:

2. ArrayList ai;
3. 
   
4. void setup(){
5.   ai = new ArrayList();
6.   for(int i=0;i<10;i++){
7.     ai.add(i);
8.   }
9. }

just tried, but cant reproduce your error (winXP, 32 bit).

are you using processing 1.5 or 1.5.1? however, in both versions, i dont get this error.


this error is mentioned here: (but still strange, because your code should actually work)
http://processing.googlecode.com/svn/trunk/processing/build/shared/revisions.txt

+ 'unexpected token void' for any type of error (due to fallback)
  http://code.google.com/p/processing/issues/detail?id=551