{"id":3005,"date":"2020-04-30T18:54:38","date_gmt":"2020-04-30T13:24:38","guid":{"rendered":"https:\/\/www.h2kinfosys.com\/blog\/?p=3005"},"modified":"2022-07-21T15:46:30","modified_gmt":"2022-07-21T10:16:30","slug":"collection-hierarchy","status":"publish","type":"post","link":"https:\/\/www.h2kinfosys.com\/blog\/collection-hierarchy\/","title":{"rendered":"Collection Hierarchy"},"content":{"rendered":"

Java Collection framework<\/a> consists of Interfaces and Classes. It works with different types of collections such as List, Set, and Tree, etc.<\/span><\/p>\n

The below diagram shows the collection framework hierarchy<\/a>.<\/span><\/em><\/p>\n

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Collection framework mainly consists of four interfaces:<\/strong><\/h2>\n

1] List: <\/b>It contains elements arranged in sequential order, and these elements can be accessed by using their index position (starting from 0). It implements ArrayList, Vector, and VectorList. Elements can be inserted in the list at any position but can be retrieved in the same order in which they are added. It can also store duplicate elements.<\/span><\/p>\n

2] Queue:<\/b> Queue contains similar elements in which new elements are added from one end, whereas removed from the other end (FIFO \u2013 First In First Out). It implements LinkedList and PriorityQueue.<\/span><\/p>\n

3] Set: <\/b>Set is used to store the collection of unique elements<\/a>. Duplicacy is not allowed in the Set. It does not store the elements in sequential order. While accessing the elements, we may not get the elements in the same order in which they are stored. HashSet, LinkedHashSet, and TreeSet implements the Set interface. Elements in the Set can only be iterated using Iterator.<\/span><\/p>\n

4] Map: <\/b>Map stores the elements in the form of Key\/Value pairs. It is extended by SortedMap and implemented by HashMap and HashTable. It does not contain duplicate values, and each key can, at most, store one value.<\/span><\/p>\n