When an object to be the target of the "foreach" statement?

for-each loop:

Implementing Iterable interface allows an object to be the target of the "foreach" statement.

java.lang
Interface Iterable<T>

All Known Subinterfaces:

BeanContext, BeanContextServices, BlockingDeque<E>, BlockingQueue<E>, Collection<E>, Deque<E>, List<E>, NavigableSet<E>, Queue<E>, Set<E>, SortedSet<E>

So we can Iterate List, Set, SortedSet, Collection..etc Objects.

sources :http://docs.oracle.com/javase/6/docs/api/java/lang/Iterable.html