A little history

Java collection framework is an object oriented framework for dealing with data vectors. It started with JDK 1.2 and is today is very popular. There are well-known Collection classes like

• ArrayList,
• LinkedList,
• TreeSet,
• HashSet,
• LinkedHashSet,
• ArrayDeque, a double-ended queue
• Vector which is older and not popular anymore because of the synchronisation penalty you’re paying for it.