concurrency - How to handle synchronization of frequent concurrent read/writes on a Java ArrayList -

i have java class contains arraylist of transaction info objects queried , modified different threads on frequent basis. @ basic level, structure of class looks (currently no synchronization present):

class statistics {     private list<traninfo> traninfolist = new arraylist<traninfo>();      // method runs - every time transaction comes in.     void add(traninfo traninfo)     {         traninfolist.add(traninfo);     }      // method acts cleaner , runs occasionally.            void removebasedonsomecondition()     {         // code determine items remove          traninfolist.removeall(listofunwantedtraninfos);     }      // methods query stats on tran info.     // these methods called frequently.     stats getstatsbasedonsomecondition()     {         // iterate on list of tran info         // objects , return stats     }       stats getstatsbasedonsomeothercondition()     {         // iterate on list of tran info         // objects , return stats     } } 

i need ensure read/write operations on list synchronized correctly, however, performance important, don't want end locking in every method call (especially concurrent read operations). i've looked @ following solutions:

copyonwritearraylist

i've looked @ use of copyonwritearraylist prevent concurrentmodificationexceptions being thrown when list modified while iterating on it; problem here copy required each time list modified... seems expensive given how list modified , potential size of list.

readwritelock

a readwritelock used synchronize read/write operations while allowing concurrent read operations take place. while approach work, ends resulting in lot of synchronization code in class (this isn't end of world though).

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are there other clever ways of achieving kind of synchronization without big performance penalty, or 1 of above methods recommended way? advice on appreciated.

i'd use collections.synchronizedlist() until know sure indeed crucial performance bottle neck of application (needless doubt ;-)). can know sure through thorough testing. assume know "premature optimization"...

if strive optimize access list i'd readwritelock approach.