Java collections concept
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This document discusses the collection framework in Java. It provides an overview of the need for collections due to limitations of arrays. It then describes the key interfaces in the collection framework - Collection, List, Set, SortedSet, NavigableSet, Queue, Map, SortedMap, and NavigableMap. For each interface, it provides a brief description of its purpose and characteristics. It explains that collections allow storing heterogeneous data types with variable sizes, unlike arrays.
Java collections concept
- 1. Collection Framework concept in Java Kumar Gaurav [email protected]
- 2. Need of collection framework? Due to limitation of arrays Arrays store homogenous data types only and fixed size Collections allowed to store heterogeneous data types with growable size Collection Framework is set of several classes and interfaces that helps to achieve this target
- 3. 9 key interfaces of collection framework Collection List Set SortedSet NavigableSet Queue Map SortedMap NavigbleMap
- 4. 1- Collection Whenever we would like to represent a group of objects as a single entity, we use Collection for the same It is also known as root interface of collections framework but not completely There is no concrete class that implements collection interface directly It defines most common methods which are applicable on any collection object -
- 5. 2- List List is child interface of Collection Representing a group of object as a single entity with the condition that - Duplicates are allowed Insertion order is preserved Duplicates identified by index Preserving insertion order by index Index has very important role
- 6. 3- Set It is child interface of Collection Representing a group of object as a single entity with the condition that - Duplicates are not allowed Insertion order is not preserved
- 7. 4- SortedSet It is child interface of Set Representing a group of object as a single entity with the condition that - Duplicates are not allowed Insertion order is not preserved Objects should be stored in some sorted order
- 8. 5- NavigableSet It is child interface of SoretdSet It defines several methods for navigation purpose TreeSet is the implementation class
- 9. 6- Queue It is the child interface of Collection If we want to represent a group of objects prior to processing then we should go for Queue For e.g. suppose we have to send email to 100 email id’s so we have to store it somewhere and the emails will be delivered in the same order they were saved
- 10. Wait a min before next… All discussed 6 interfaces Collection, List, Set, SoretdSet, NavigableSet, Queue meant for representing a group of individual object as a single entity If we want a represent group of objects as key-value pairs then we should go for Map interface
- 11. 7- Map Map interface is not the child of Collection interface If we want to represent a group of objects as key-value pairs then should go for Map Both key and value are objects Duplicate key is not allowed, value can be duplicate
- 12. 8- SortedMap It is the child interface of Map If we want to represent a group of key value pairs as per some sorting order then SortedMap is used
- 13. 9- NavigableMap It is the child interface of SoretdMap It defines several utility methods for navigation purpose TrreeMap is the implementation class
- 14. References Durgasoft java tutorial http://durgasoft.com/ Oracle https://docs.oracle.com/javase/7/docs/api/java/util/Collections.html
- 15. Thank you!