5.1. Java Collection

1. Difference between Collection and Collections

Key	Collection	Collections
Basic	interface in Java collection framework	utility class in Collection framework
Static Methods	doesn't has all static methods	has all static method
Operation	used to store list of object in a single object	used to operate on collection.

Difference between ArrayList, LinkedList and Vector.

Difference between HashSet,LinkedHashSet and Treeset.

What is legacy class?

What is concurrentModificationException?

What is the difference between Hashtable and HashMap?

What is concurrentHashMap?

Is Map comes under collection framework?

No. Map interface has key and value pair stored under the common name. Cursor available under collection hierarchy such as Iterator, ListIterator, Enumeration and foreach doesn't iterates the map interface variable.