An In-Depth Guide to LinkedHashSet in Java

A Guide to LinkedHashSet in Java

LinkedHashSet is a powerful data structure that is part of the Java Collections framework. It is a member of the Set interface and is similar to HashSet but maintains the order of elements added to it. LinkedHashSet maintains a doubly-linked list internally between its entries so that the insertion order is preserved. This makes LinkedHashSet useful when you need to preserve the order of elements.

Advantages of LinkedHashSet

• The LinkedHashSet maintains the insertion order.
• It can be used when you need fast lookup of elements, like a hash table.
• It is not synchronized and therefore provides better performance than HashSet or TreeSet.
• The performance of LinkedHashSet is same as HashSet when dealing with unordered sets.

Disadvantages of LinkedHashSet

• It has more overhead compared to HashSet because of the linked list that is maintained internally.
• It requires more memory compared to HashSet because of the additional overhead.
• It is not suitable for the situation where faster lookup is required.

How to use LinkedHashSet

LinkedHashSet can be used just like any other collection classes such as ArrayList. For example, to create a LinkedHashSet, you can use the following code:

LinkedHashSet<String> mySet = new LinkedHashSet<>();

mySet.add("Foo");
mySet.add("Bar");
mySet.add("Baz");

System.out.println(mySet);

The output would be [Foo, Bar, Baz]. As you can see, the elements are printed in the same order they were added.

You can also iterate through LinkedHashSet just like any other collection by using the for-each loop or iterator. For example:

for (String element : mySet) {
  System.out.println(element);
}

And the output would be:

Foo
Bar
Baz

LinkedHashSet is an important data structure in Java that allows for fast lookups and preserves the insertion order. It is useful in situations where you need to maintain the order of the elements.