{"id":375,"date":"2025-07-01T12:45:07","date_gmt":"2025-07-01T12:45:07","guid":{"rendered":"https:\/\/thetestdata.com\/blog\/?p=375"},"modified":"2025-07-16T09:51:07","modified_gmt":"2025-07-16T09:51:07","slug":"difference-between-arraylist-and-linked-listin-which-situation-they-are-used","status":"publish","type":"post","link":"https:\/\/thetestdata.com\/blog\/difference-between-arraylist-and-linked-listin-which-situation-they-are-used\/","title":{"rendered":"Difference between Arraylist and Linked List,In which situation they are used ?"},"content":{"rendered":"\n

\ud83c\udd9a ArrayList<\/code> vs LinkedList<\/code> \u2013 Core Differences<\/p>\n\n\n\n

Feature<\/th>ArrayList<\/code><\/th>LinkedList<\/code><\/th><\/tr><\/thead>
Internal structure<\/strong><\/td>Dynamic array<\/td>Doubly linked list<\/td><\/tr>
Access (get\/set)<\/strong><\/td>\ud83d\udd25 Fast (O(1))<\/td>\ud83d\udc22 Slower (O(n))<\/td><\/tr>
Insert\/Delete at start or middle<\/strong><\/td>\ud83d\udc0c Slow (O(n)) due to shifting<\/td>\u26a1 Fast (O(1) at head\/tail)<\/td><\/tr>
Memory overhead<\/strong><\/td>Low (array only)<\/td>High (nodes + pointers)<\/td><\/tr>
Iteration<\/strong><\/td>Faster due to array locality<\/td>Slightly slower<\/td><\/tr>
Thread-safe?<\/strong><\/td>\u274c Not thread-safe (unless synchronized manually)<\/td>\u274c Same<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\ud83e\udde0 When to Use Each<\/strong><\/p>\n\n\n\n

\u2705 Use ArrayList<\/code> when:<\/p>\n\n\n\n

    \n
  • You need fast random access<\/strong> using index (get(i)<\/code>)<\/li>\n\n\n\n
  • You mostly add\/remove elements at the end<\/strong><\/li>\n\n\n\n
  • Memory usage should be optimized<\/li>\n<\/ul>\n\n\n\n

    \u2705 Example<\/strong>:<\/p>\n\n\n\n

    List<String> cities = new ArrayList<>();\ncities.add(\"Mumbai\");\nSystem.out.println(cities.get(0)); \/\/ Very fast<\/code><\/pre>\n\n\n\n
    \n\n\n\n
    \u2705 Use LinkedList<\/code> when:<\/p>\n\n\n\n
      \n
    • You have frequent insertions\/deletions<\/strong> at the start, middle, or both ends<\/li>\n\n\n\n
    • You\u2019re implementing a queue, stack, or deque<\/strong><\/li>\n\n\n\n
    • You don\u2019t care much about random access performance<\/li>\n<\/ul>\n\n\n\n
      \u2705 Example:<\/strong><\/p>\n\n\n\n
      Queue<String> tasks = new LinkedList<>();\ntasks.add(\"Task 1\");\ntasks.remove(); \/\/ Fast removal at head<\/code><\/pre>\n\n\n\n
      \ud83e\uddd1\u200d\ud83d\udcbc Interview-Ready Takeaways<\/strong><\/p>\n\n\n\n
      Question<\/th>Key Points<\/th><\/tr><\/thead>
      Which is faster for search?<\/td>ArrayList<\/code>\u2014because of direct index access<\/td><\/tr>
      Which is better for adding\/removing in middle?<\/td>LinkedList<\/code>\u2014no shifting elements<\/td><\/tr>
      Can you use both for implementing queues?<\/td>Yes\u2014but LinkedList<\/code> is more natural (supports queue ops)<\/td><\/tr>
      When would you avoid using LinkedList?<\/td>If memory is critical or you need fast access<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"
      Explore the differences between ArrayList and LinkedList in Java. Learn their use cases, performance traits, and how to pick the right one for your needs.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-container-style":"default","site-container-layout":"default","site-sidebar-layout":"default","disable-article-header":"default","disable-site-header":"default","disable-site-footer":"default","disable-content-area-spacing":"default","footnotes":""},"categories":[17],"tags":[],"class_list":["post-375","post","type-post","status-publish","format-standard","hentry","category-java-interview-questions"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts\/375","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/comments?post=375"}],"version-history":[{"count":2,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts\/375\/revisions"}],"predecessor-version":[{"id":409,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/posts\/375\/revisions\/409"}],"wp:attachment":[{"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/media?parent=375"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/categories?post=375"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thetestdata.com\/blog\/wp-json\/wp\/v2\/tags?post=375"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}