How do I create a Linked List Data Structure in Java

Question

What s the best way to make a linked list in Java

User · Answer

Use java util LinkedList  Like this   list   new java util LinkedList

User · Answer

The obvious solution to developers familiar to Java is to use the LinkedList class already provided in java util  Say  however  you wanted to make your own implementation for some reason  Here is a quick example of a linked list that inserts a new link at the beginning of the list  deletes from the beginning of the list and loops through the list to print the links contained in it  Enhancements to this implementation include making it a double-linked list  adding methods to insert and delete from the middle or end  and by adding get and sort methods as well    Note  In the example  the Link object doesn t actually contain another Link object -  nextLink is actually only a reference to another link    class Link       public int data1      public double data2      public Link nextLink         Link constructor     public Link int d1  double d2            data1   d1          data2   d2               Print Link data     public void printLink             System out print       data1          data2                   class LinkList       private Link first         LinkList constructor     public LinkList             first   null               Returns true if list is empty     public boolean isEmpty             return first    null               Inserts a new Link at the first of the list     public void insert int d1  double d2            Link link   new Link d1  d2           link nextLink   first          first   link               Deletes the link at the first of the list     public Link delete             Link temp   first          if first    null            return null             throw new NoSuchElementException       this is the better way                     first   first nextLink          return temp               Prints list data     public void printList             Link currentLink   first          System out print  List              while currentLink    null                currentLink printLink                currentLink   currentLink nextLink                    System out println                 class LinkListTest       public static void main String   args            LinkList list   new LinkList             list insert 1  1 01           list insert 2  2 02           list insert 3  3 03           list insert 4  4 04           list insert 5  5 05            list printList             while  list isEmpty                  Link deletedLink   list delete                System out print  deleted                  deletedLink printLink                System out println                        list printList

User · Answer

slightly improved code without using collection framework  package com test   public class TestClass        private static Link last      private static Link first       public static void main String   args               Inserting         for int i 0 i lt 5 i                 Link insert i 5                     Link printList               Deleting         Link deletefromFirst            Link printList                protected  static class Link           private int data          private Link nextlink           public Link int d1                this data   d1                     public static void insert int d1                Link a   new Link d1               a nextlink   null              if  first    null                    last nextlink   a                  last   a                else                   first   a                  last   a                            System out println  Inserted -   d1                      public static void deletefromFirst                 if null  first                                System out println  Deleting -   first data                   first   first nextlink                            else                  System out println  No elements in Linked List                                     public static void printList                 System out println  Elements in the list are                System out println  -------------------------                Link temp   first              while  temp    null                    System out println temp data                   temp   temp nextlink

User · Answer

Its much better to use java util LinkedList  because it s probably much more optimized  than the one that you will write

User · Answer

The above linked list display in opposite direction  I think the correct implementation of insert method should be  public void insert int d1  double d2         Link link   new Link d1  d2         if first  null           link nextLink   null          first   link           last link            else          last nextLink link          link nextLink null          last link

User · Answer

Java has a LinkedList implementation  that you might wanna check out  You can download the JDK and it s sources at java sun com

[java] How do I create a Linked List Data Structure in Java?

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