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LinkedHashSet in Java

Last Updated : 24 Oct, 2025
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LinkedHashSet in Java implements the Set interface of the Collection Framework.

  • Combines the functionalities of a HashSet with an internal list to maintain the insertion order of elements.
  • LinkedHashSet stores unique elements only and allows a single null.
  • Implements Set, Cloneable, and Serializable interfaces.
Java 
import java.util.LinkedHashSet;

public class Geeks {
    public static void main(String[] args) {
      
        // Create a LinkedHashSet of Strings
        LinkedHashSet<String> set = new LinkedHashSet<>();
        set.add("Apple");
        set.add("Banana");
        set.add("Cherry");
        set.add("Apple");
        System.out.println("" + set);
    }
}

Output
[Apple, Banana, Cherry]

Hierarchy of LinkedHashSet

It implements the Set interface, which is a sub-interface of the Collection interface.

2

Constructors of LinkedHashSet

1. LinkedHashSet()

This constructor is used to create an empty LinkedHashSet with the default capacity i.e. 16 and load factor 0.75.

LinkedHashSet<E> hs = new LinkedHashSet<E>();

2. LinkedHashSet(Collection C)

Used in initializing the HashSet with the elements of the collection C.

LinkedHashSet<E> hs = new LinkedHashSet<E>(Collection c);

3. LinkedHashSet(int size)

Used to initialize the size of the LinkedHashSet with the integer mentioned in the parameter.

LinkedHashSet<E> hs = new LinkedHashSet<E>(int size);

4. LinkedHashSet(int capacity, float fillRatio)

Creates an empty LinkedHashSet with specified capacity and load factor.

LinkedHashSet<E> hs = new LinkedHashSet<E>(int capacity, int fillRatio);

Performing Various Operations on LinkedHashSet

Let’s see how to perform a few frequently used operations on the LinkedHashSet.

1. Adding Elements in LinkedHashSet

In order to add an element to the LinkedHashSet, we can use the add() method. This is different from HashSet because in HashSet, the insertion order is not retained but is retained in the LinkedHashSet.

Java 
import java.io.*;
import java.util.*;

class Geeks {

    public static void main(String[] args) {

        // Creating an empty LinkedHashSet
        LinkedHashSet<String> lh = new LinkedHashSet<String>();

        // Adding elements to above Set using add() method
        lh.add("Geek");
        lh.add("For");
        lh.add("Geeks");

        System.out.println("LinkedHashSet : " + lh);
    }
}

Output
LinkedHashSet : [Geek, For, Geeks]

2. Removing Elements in LinkedHashSet

The values can be removed from the LinkedHashSet using the remove() method.

Java 
import java.io.*;
import java.util.*;

class Geeks {

    public static void main(String[] args) {

        // Creating an empty LinekdhashSet of string type
        LinkedHashSet<String> lh
            = new LinkedHashSet<String>();

        // Adding elements to above Set using add() method
        lh.add("Geek");
        lh.add("For");
        lh.add("Geeks");
        lh.add("A");
        lh.add("B");
        lh.add("Z");

        System.out.println("" + lh);

        // Removing the element from above Set
        lh.remove("B");

        // Again removing the element
        System.out.println("After removing element " + lh);

        // Returning false if the element is not present
        System.out.println(lh.remove("AC"));
    }
}

Output
[Geek, For, Geeks, A, B, Z]
After removing element [Geek, For, Geeks, A, Z]
false

3. Iterating through the LinkedHashSet

Iterate through the elements of  LinkedHashSet using the iterator() method. The most famous one is to use the enhanced for loop.

Java 
import java.io.*;
import java.util.*;

class Geeks {

    public static void main(String[] args) {

        Set<String> lh = new LinkedHashSet<String>();

        lh.add("Geek");
        lh.add("For");
        lh.add("Geeks");
        lh.add("A");
        lh.add("B");
        lh.add("Z");

        Iterator itr = lh.iterator();

        while (itr.hasNext())
            System.out.print(itr.next() + ", ");

        System.out.println();

        for (String s : lh)
            System.out.print(s + ", ");
        System.out.println();
    }
}

Output
Geek, For, Geeks, A, B, Z, 
Geek, For, Geeks, A, B, Z,

Methods of LinkedHashSet

MethodDescription
add(E e)Adds an element if it’s not already present.
addAll(Collection c)Adds all elements from the specified collection.
clear()Removes all elements from the set.
contains(Object o)Checks if the set contains the specified element.
containsAll(Collection c)Checks if the set contains all elements from the given collection.
remove(Object o)Removes the specified element from the set.
removeAll(Collection c)Removes all matching elements from the set.
retainAll(Collection c)Keeps only elements present in the given collection.
isEmpty()Checks if the set is empty.
size()Returns the number of elements in the set.
iterator()Returns an iterator over the elements.
toArray()Returns an array containing all elements.
toArray(T[] a)Returns an array of the specified type containing all elements.
hashCode()Returns hash code of the set.
equals(Object o)Compares this set with another set.
clone()Creates a shallow copy of the set.
toString()Returns a string representation of the set.
spliterator()Returns a Spliterator for this set.


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