Learn Set in Java

Hello Readers,

Today we will see what is Set in Java.

Set is nothing but a interface which is a part of Collection framework and utils package.

Set Implement Collection interface and implemented few important classes which we will see.

• Set has below implementation :
• HashSet
• HashSet does not preserve insertion order istead it preserves sorting order.
• HashSet have default capacity of 16 and has load factor of 75% which means if hashset get filled up to 75% then its capacity will get increased.
• we also provide capacity and load factor inside its constructor parameter.
• we can pass any collection object to hashset constructor.
• It doesn't allow duplicate values.
• it allow different type of objects to add.
• Hashset have one child class which is LinkedHAshSet.
• It preserve insertion order.
• HashTable and Doubly Linked List are used.
• its default capacity is 16 and other cosntructors are like hashset constructor.
• it uses doubly linked list and hashtable for formation of linked hash set.

• LinkedHashSet:- 
• It is very useful implementation which help us in many way.
• It preserve insertion order which is not happen in HashSet.
• It allow 1 null value.
• As it implements Set interface it obviously takes only unique element.

• SortedSet:-
• It is a another type of Set implemenation class.
• It implement set interface.
• In this set duplicates are not allowed.
• It preserve sorting order; it store values in sorted order.
• NavigableSet:-
• It is a child interface which is implemented by TreeSet.
• It have some addtional method to navigate the set.
• TreeSet:-
• Its a implementation class of Navigable set.
• It preserve natural sorting order .
• It does not allow homogeneous objects means only same type of objects are allowed.
• It does not allow null values in it.
• Duplicate values are not allowed.
• there are 4 constructor:
• TreeSet()
• TreeSet(Comparator c)
• for custom sorting
• TreeSet(Collection c)
• we can pass any collection object in it.
• TreeSet(SortedSet s)
• Default natural sorting is applicable for String and integer data types only. reason behind it is  compareTo() function of comparable interface is implemented by string, integer and wrapper classes.
• Those who not implemented that comparable interface will not get natural sorting.

This was all about Set interface I hope it will help you increase your knowledge and understand easily.