1) Collection interface is child of Iterable interface .

2) Collection interface provided the most common methods , which can be applied for any collection object

3) Following is the list of methods present in Collection interface .

   1) boolean add(E e)
   2) boolean addAll(Collection c)
   3) void clear()
   4) boolean contains(Object o)
   5) boolean containsAll(Collection c)
   6) boolean isEmpty()
   7) Iterator iterator()
   8) boolean remove(Object o)
   9) boolean removeAll(Collection c)
   10) boolean retainAll(Collection c)
   11) int size()
   12) Object[] toArray()
   13) T[] toArray(T[] a)