Set (Interface) & Child Classes of Set Interface

Set

• Set is Child Interface of Collection.
• If we want to represent a group of Individual Object as a Single entity, Where Duplicates are not allowed & Insertion Order Not Preserved.
• Set Interface doesn't have Contain any New Method and we have to use Only Collection Interface Method.
• 

HashSet(Interface)

• The Underlying Data Structure is HashTable.
• Duplicates objects are not allowed.
• Insertion Order is not Preserved & It is based on Hash Code of Objects.
• Null Insertion is Possible.
• Heterogeneous Objects are allowed.
• Implements Serializable & Cloneable but Not Random Access Interface.
• Hash Set is the Best choice If Our Frequent Operation is Search Operation.

Note:

• In HashSet Duplicates are Not allowed, If we are trying to Insert Duplicates than we won't get any Compile/Run Time errors & add Method Simply Returns False.

Constructor

1. HashSet h = new HashSet();

• Creates an Empty HashSet Objects with Default Intial Capacity is 16 & Default Fill Ratio 0.75.

  2.HashSet h = new HashSet(int intialCapacity);

• Creates an Empty HashSet Objects with Specified Intial Capacity & Default Fill Ratio 0.75.

  3.HashSet h = new HashSet(int intialCapacity,float fillRatio);

  4.HashSet h = new HashSet(Collection c);

• Creates an Equivalent HashSet for the given Collection.
• This Constructor meant for Inter Conversion B/W Collection Objects.

LinkedHashSet

• It is Child Class of HashSet.
• It is Exactly Same as HashSet {Including Constructor & Method}.

 Except Some Differences B/W HashSet & LinkedHashSet.

SortedSet

• It is a Child Interface of Set.
• If we want to Represent A group of Individual Objects according to Some Sorting Order without Duplication than we should go for SorteSet.

Methods of SortedSet

• first()-> (1oo)[Return First element].
• last()->   (110)[Return Last element].
• headSet()->(100,101,102)[Return less than object].
• tailSet()-> (106,108,110)[Return greater than object].
• subSet()-> [Return greater & equal(>=) than object & less than & equal(<=) than object].
• comparator()-> Returns Describe underlying Sorting Technique. if we are using Default Natural Sorting Order than we will get Null. 
• for eg:

100

101

102

104

106

108

110
Note:-

• Numbers-> Default Natural Sortiong Order [Ascending Order]
• String ->Default Natural Sorting Order [Ascending Order]

NavigableSet

• NavigableSet is Child class of Sorted Interface.
• Duplication are Not allowed.
• Insertion Order Not Preserved.
• Heterogeneous Objects are allowed.
• Null Insertion is Possible.
• NavigableSet implements Serializable & Cloneable but not Random Access Interface.
• NavigableSet interface provides navigation methods and descending iterator that allows the elements in the set can be traversed in descending order.

TreeSet

• The Underlying Data Structure is Balanced Tree.
• Duplication are Not allowed.
• Insertion Order Not Preserved.
• Heterogeneous Objects are Not allowed.
• Null Insertion is Possible.
• TreeSet implements Serializable & Cloneable but Not Random Access Interface.
• All Objects will be Inserted based On some Sorting Order.
• It may be Default Natural Sorting Order .

Constructor

1. TreeSet t = new TreeSet();

• Create an Empty TreeSet Object where, the elements will be Inserted according to Default Natural Sorting Order.

  2.TreeSet t = new TreeSet(Comparable c);

• Create an Empty TreeSet Objects where, the elements will be Inserted according to Customizer Sorting Order Specified by Comparator Object.

  3.TreeSet t = new TreeSet (Collection c);

  4.TreeSet t = new TreeSet (SortedSet s);