https://github.com/mukul273/java-collections

Java Collections for beginners
https://github.com/mukul273/java-collections

collections git github java

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Java Collections for beginners

• Host: GitHub
• URL: https://github.com/mukul273/java-collections
• Owner: mukul273
• Created: 2017-03-18T05:29:10.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2017-03-21T19:43:18.000Z (over 9 years ago)
• Last Synced: 2025-02-15T19:49:07.342Z (over 1 year ago)
• Topics: collections, git, github, java
• Language: Java
• Size: 1.13 MB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
This is for Basic understanding of Java Collections Framework.

/* 

         * Consider:

         * 1. what you need the collection to do

         * 2. are you using the fastest collection for your purposes

         * (think about insertion/deletion, retrieval and traversal

         */

         

        //////////////// LISTS ///////////////////////////////////

         

        // Store lists of objects

        // Duplicates are allowed

        // Objects remain in order

        // Elements are indexed via an integer

        // cf. shopping list

        // Checking for particular item in list is slow

        // Looking an item up by index is fast

        // Iterating through lists is relatively fast

        // Note: you can sort lists if you want to.

         

        // If you only add or remove items at end of list, use ArrayList.

        List list1 = new ArrayList();

         

        // Removing or adding items elsewhere in the list?

        List list2 = new LinkedList();

         

        ////////////////SETS ///////////////////////////////////

         

        // Only store unique values

        // Great for removing duplicates

        // Not indexed, unlike lists

        // Very fast to check if a particular object exists

        // If you want to use your own objects, you must implement hashCode() and equals().

         

        // Order is unimportant and OK if it changes?

        // HashSet is not ordered.

        Set set1 = new HashSet();

         

        // Sorted in natural order? Use TreeSet - must implement Comparable for custom types

        // (1,2,3 ..., a,b,c.... etc)

        Set set2 = new TreeSet();

         

        // Elements remain in order they were added

        Set set3 = new LinkedHashSet();

         

        ////////////////MAPS ///////////////////////////////////

         

        // Key value pairs.

        // Like lookup tables

        // Retrieving a value by key is fast

        // Iterating over map values is very slow

        // Maps not really optimised for iteration

        // If you want to use your own objects as keys, you must implement hashCode() and equals().

         

        // Keys not in any particular order, and order liable to change.

        Map map1 = new HashMap();

         

        // Keys sorted in natural order - must implement Comparable for custom types

        Map map2 = new TreeMap();

         

        // Keys remain in order added 

        Map map3 = new LinkedHashMap();

         

        // There are also the SortedSet and SortedMap interfaces.