By using String or String Buffer performance increases?

Collection frame work

  Introduction

   The Interfaces from Collection framework

Collection

   Collection interface
   Add elements to a collection
   Is it contained in the collection
   Compare two collections
   Remove elements from a collection
   Convert collection to Array
   Get the size of a Collection
   Is a collection empty
   Clear a collection
   Get the iterator() from a collection

List

  List

    List interface
    Add element to List
    Clear a List
    Does it contain certain element
    Compare two Lists
    Get the element index
    Get Iterator from a List
    Remove element from List
    Get/set element
    List size and empty flag
    Get the sub list from a list
    Convert List to Array

ArrayList

    ArrayList Class
    Create ArrayList object
    Add to ArrayList
    Clear an ArrayList
    Shallow copy of current ArrayList
    If contain a certain object
    Increases the capacity of an ArrayList
    Get/Replace element by index
    Get object for index
    Remove from ArrayList
    Get the size and trim to size
    If ArrayList is empty
    Convert ArrayList to array

LinkedList

    LinkedList class
    Create LinkedList
    Add element to LinkedList
    Remove all elements from LinkedList
    Shallow copy of a LinkedList
    If contain a certain element
    Get iterator from LinkedList
    Peek the element
    Get the element from LinkedList
    Get the index of an element
    Poll, pop and push element to a LinkedList
    Remove element from a LinkedList
    Replace the element at the position
    Get the size of a LinkedList
    Convert LinkedList to Array

 Vector

    Vector class
    Create Vector objects
    Add elements to this vector
    Size and capacity
    Remove all elements from a vector
    Clone a vector
    Does it contain a certain element
    Copy elements in vector to an array
    Get Enumeration from this vector
    Compare two vectors
    Get element from vector
    Is vector empty
    Get element index
    Remove element from a vector
    Retain elements collection c has
    Replace element in a vector
    Get a sub list from a list
    Convert Vector to Array

  Stack

     Stack

Set

  HashSet

    HashSet class
    Add element to hash set
    Clear a hash set
    Clone a hash set
    If a hash set contain a certain element
    Is this set containing a certain element
    Get an iterator from a hash set
    Remove an element from hash set
    Get the size of a hash set

 TreeSet

    TreeSet class
    Create TreeSet objects
    Add elements to a TreeSet
    Get the least and greatest element in this TreeSet
    Clear a TreeSet
    Clone a TreeSet
    Get the comparator used by this TreeSet
    If this TreeSet contains a certain element
    Get the descending iterator and descending set
    The first and last element in this TreeSet
    Get the head set and tail set
    Is this TreeSet empty
    Get an iterator over the elements in this set in ascending order
    Get and remove first and last element in this tree
    Remove element from TreeSet
    Get the size of this TreeSet
    Get a subset from this TreeSet

 LinkedHashSet

    LinkedHashSet class
    Check if an element exists in LinkedHashSet using contains method
    Copy all elements of LinkedHashSet to an Object Array

SortedSet

 Enum

Collections

   Collections
   Get empty collection from Collections
   Do binary search
   Add to a collection
   Check collections
   Copy value to a List
   Check for common elements
   Get Enumeration from collection, create list from Enumeration
   Fill a list
   Check for frequency
   Get the index of sub list
   Get the max and min value from a Collection
   Fill n Copy object to a list
   Create set from a map
   Replace value in a list
   Reverse a list
   Get comparator in reverse order
   Rotate and shuffle a list
   Create singleton
   Sort a list
   Swap element in a list
   Get a synchronized collection
   Return an unmodifiable view of collections

 Arrays

   Arrays
   Convert array to list
   Binary search an Array
   Copy value to an Array
   Deep equals
   Deep hash code
   Deep to string
   Compare two arrays
   Fill value to array
   Get the hash code for array
   Sort an array
   Convert array to string

 Iterable

   Iterable
  Deque
   Deque

 Queue

   Queue

Comparable

   Comparable