LinkedHashSet in Java

LinkedHashSet is a class in Java that implements the Set interface and maintains insertion order while storing unique elements. It combines the features of a HashSet and a LinkedList.

• Maintains insertion order of elements
• Stores unique elements only (no duplicates)
• Provides fast performance for basic operations

[Apple, Banana, Cherry]

Note: If an element is removed and then added again, it is inserted at the end of the LinkedHashSet, because insertion order is maintained based on latest insertion.

Hierarchy of LinkedHashSet

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

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 LinkedHashSet with the elements of the collection C.

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

3. LinkedHashSet(int initialCapacity)

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

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

4. LinkedHashSet(int capacity, float fillRatio)

Creates an empty LinkedHashSet with specified capacity and load factor.

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

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.

LinkedHashSet : [Geek, For, Geeks]

2. Removing Elements in LinkedHashSet

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

[Geek, For, Geeks, A, B, Z]
After removing element [Geek, For, Geeks, A, Z]
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3. Iterating through the LinkedHashSet

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

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

Methods of LinkedHashSet