--- title: Day 149 of Learning Java & DSA: Understanding Doubly... description: An introductory exploration of Doubly Linked Lists in Java, covering the node structure with prev and next references, advantages over Singly Linked Lists... canonical: https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Day 149 of Learning Java & DSA: Understanding Doubly Linked Lists | daily.dev og:description: An introductory exploration of Doubly Linked Lists in Java, covering the node structure with prev and next references, advantages over Singly Linked Lists... og:url: https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b og:image: https://api.daily.dev/og/posts/pUmdhSx1B.png og:image:alt: Day 149 of Learning Java & DSA: Understanding Doubly Linked Lists og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Day 149 of Learning Java & DSA: Understanding Doubly Linked Lists **[Medium](https://daily.dev/sources/medium_js)** · 5 min read · 2 upvotes · 0 comments ## Summary An introductory exploration of Doubly Linked Lists in Java, covering the node structure with prev and next references, advantages over Singly Linked Lists (bidirectional traversal), limitations (extra memory, two-pointer updates), and time/space complexity. Written as a learning journal entry by a beginner studying DSA. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the difference between a singly linked list and a doubly linked list? A doubly linked list stores references to both the previous and next node in each node, while a singly linked list stores only a reference to the next node. This extra previous reference allows traversal in both forward and backward directions, unlike a singly linked list which only supports forward movement. The trade-off is increased memory usage and more complex insertion and deletion, since two references must be updated instead of one. _daily.dev surfaces data structure explainers for developers comparing linked list variants while learning DSA._ ### What is the time complexity of insertion and deletion at the beginning of a doubly linked list? Insertion at the beginning and deletion at the beginning of a doubly linked list are both O(1) operations, the same as a singly linked list. Traversal and searching remain O(n). The doubly linked list's advantage lies not in beginning-of-list complexity but in the ability to delete a node in O(1) when a direct reference to that node is already held, since both its neighbors are known. _developers studying DSA complexity trade-offs can find similar breakdowns on daily.dev._ ## Similar posts on daily.dev - [Day 199 of Learning Java & DSA: Understanding Cycle Detection in Graphs](https://daily.dev/posts/day-199-of-learning-java-dsa-understanding-cycle-detection-in-graphs-o9sqtirc5) · Medium · 5 upvotes · 0 comments - [Java List Series](https://daily.dev/posts/java-list-series-3ol6zzuck) · Baeldung · 3 upvotes · 0 comments --- Tags: [#java](https://daily.dev/tags/java), [#algorithms](https://daily.dev/tags/algorithms), [#data-structures](https://daily.dev/tags/data-structures) [View this post on daily.dev](https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Day 149 of Learning Java & DSA: Understanding Doubly Linked Lists","url":"https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b"},"datePublished":"2026-07-12T12:15:00.114Z","dateModified":"2026-09-13T19:02:17.792Z","description":"An introductory exploration of Doubly Linked Lists in Java, covering the node structure with prev and next references, advantages over Singly Linked Lists...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/54ae4f219b731340fe755550013cdd93?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/54ae4f219b731340fe755550013cdd93?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Medium","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Medium","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/medium","url":"https://daily.dev/sources/medium_js"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"java,algorithms,data-structures","timeRequired":"PT5M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Medium","item":"https://daily.dev/sources/medium_js"},{"@type":"ListItem","position":3,"name":"Day 149 of Learning Java & DSA: Understanding Doubly Linked Lists"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/day-149-of-learning-java-dsa-understanding-doubly-linked-lists-pumdhsx1b#faq","mainEntity":[{"@type":"Question","name":"What is the difference between a singly linked list and a doubly linked list?","acceptedAnswer":{"@type":"Answer","text":"A doubly linked list stores references to both the previous and next node in each node, while a singly linked list stores only a reference to the next node. 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