Performance Improvement techniques in Collections

Lists:

1. Use ArrayList with proper initialization if you don't want thread safe for the collection whenever you  add/remove/access objects at end and middle of collection.
2. Use Vector with proper initialization if you want thread safe for the collection whenever you  add/remove/access objects at end and middle of collection.
3. Use LinkedList if you don't want thread safe for the collection whenever you  add/remove/access objects at beginning of collection.
4. Use synchronized LinkedList if you want thread safe for the collection whenever you add/remove/access objects at beginning of collection.
5. Use ListIterator than Iterator and Enumeration for List types

 

Sets:

1. Use HashSet for maintaining unique objects if you don't want thread safe for the collection for all basic(add/remove/access) operations otherwise use synchronized HashSet for thread safe.
2. Use TreeSet for ordered and sorted set of unique objects for non-thread safe collection otherwise use synchronized TreeSet for thread safe

Maps:

1. Use HashMap for non-thread safe map collection otherwise use Hashtable for thread safe collection.
2. Use TreeMap for non-thread safe ordered map collection otherwise use synchronized.
3. TreeMap for thread safe.