java - guava-libraries: is Iterators.cycle() thread-safe? -

suppose have following class:

public class foo {        private list<integer> list = lists.newarraylist(1, 2, 3, 4, 5);     private iterator<integer> iterator = iterators.cycle(list);        public void bar(){           integer value = iterator.next();           dosomethingwithaninteger(value);     }   }   

if instance of foo acessed simultaneously 2 threads, need each thread gets different value iterator.next(). bar() method have made synchronized? or iterator.next() guaranteed thread-safe?

in example, using arraylist underlying iterable. thread-safety of cyclic iterator depend on specific iterable implementation?

thank you.

pretty nothing in guava guaranteed thread safe unless documented such.

you not have synchronize entire bar method, should wrap call iterator.next() in synchronized block. eg:

public void bar(){       integer value;     synchronized (iterator) {         value = iterator.next();       }     dosomethingwithaninteger(value); }