Differences Between HashSet and LinkedHashSet

HashSet

Before learning about the difference between HashSet and LinkedHashSet, let us learn about HashSet first.

In Java programming, the HashSet is a strong and extensively used collection that offers a distinct approach to dealing with sets of data. So, what precisely is a HashSet and how does it simplify our life as Java developers?

In basic words, a HashSet is a collection that does not allow duplicate entries and does not ensure element order. Now let's look at its declaration and how it may be utilised.

To declare a HashSet in Java, you can use the following syntax:

Replace Type with the specific type of element you wish to store in the HashSet. This short line lays the groundwork for establishing a HashSet, which will automatically handle duplicates and allow quick access to components.

Now, let us explore a brief example to demonstrate the actual application of HashSet:

In this example, we generate a HashSet of strings, add several programming languages to it, and then display the HashSet. The appeal of HashSet rests in its simplicity and effectiveness, making it an indispensable tool in Java programming for easily handling unique collections. So, the next time you need a collection that provides uniqueness without regard for order, try using the HashSet in your Java toolkit.

To learn more about HashSet in Java, click here.

LinkedHashSet

Before learning about the difference between HashSet and LinkedHashSet, let us now learn about LinkedHashSet.

In Java collections, the LinkedHashSetstands out as an intriguing solution, combining the best of HashSet and LinkedHashSet. It combines the uniqueness of components, such as HashSet, with the ordered iteration of elements, similar to LinkedHashSet. Let's take a quick look at the definition of LinkedHashSetand provide an example.

Declaration:

Here, we declare a LinkedHashSet named linkedSet capable of holding strings. Unlike traditional sets, this one maintains the order in which elements are inserted.

Example:

In this example, we add fruits to our LinkedSet, showcasing its uniqueness feature – duplicate elements are automatically rejected. When we print the set, the order of insertion is retained, offering a predictable and orderly output.

LinkedHashSet is an excellent solution when you require a collection that combines the features of a set with a linked list. Whether you need to preserve insertion order or ensure uniqueness, LinkedHashSet offers an attractive solution amid the huge terrain of Java collections. It's a flexible tool that works in situations where keeping order is as important as preventing duplication.

Differences Between HashSet and LinkedHashSet

Let us now learn about the difference between HashSet and LinkedHashSet.

Understanding the differences between various data structures is necessary for effective Java collection development. Two regularly used classes, HashSet and LinkedHashSet, may appear identical at first look, but they have significant properties that might affect the efficiency of your code. Let's look at the distinctions between these two classes in a user-friendly tabular style.

Similarities Between HashSet, LinkedHashSet

After learning about the difference between HashSet and LinkedHashSet, let use learn about some of their similarities.

In Java collections, HashSet and LinkedHashSet compete for attention, each offering unique functionality while having fascinating commonalities. Despite their differences in implementation, these two classes have characteristics that make them vital candidates for collection management.

First and foremost, both HashSet and LinkedHashSet are part of the java.util package, emphasizing their shared origins. At its fundamental, they are based on the Set interface, which includes the fundamental concepts of uniqueness and the lack of duplication among their elements.

A striking similarity lies in their commitment to constant-time complexity for basic operations such as add, remove, and contain. Whether you're leveraging the lightning-fast hashing mechanism of HashSet or the doubly-linked structure of LinkedHashSet, the efficiency remains unwavering.

Furthermore, these siblings share the trait of non-synchronized behaviour. This characteristic makes them ideal for scenarios where thread safety is not a primary concern, allowing for quicker and more efficient operations in single-threaded environments.

In terms of iteration, both HashSet and LinkedHashSet have iterators that traverse entries in the order they were added. This order-preserving property is a notable commonality, particularly when the sequence of element addition is important in your application logic.

In essence, HashSet and LinkedHashSet appear to be separate entities with distinct characteristics, yet under the surface, they share a connection that demonstrates the beauty of Java's collection system. Understanding their commonalities allows developers to make educated decisions, ensuring that their chosen set implementation is smoothly aligned with the unique demands of their applications.

When to Use HashSet and LinkedHashSet in Java

So, after learning about the difference between HashSet and LinkedHashSet, we know when we should use HashSet and LinkedHashSet in Java. Let us dive deep into its use case.

HashSet and LinkedHashSetare two key Java classes that deal with sets and provide different features based on certain use scenarios. Understanding whether to utilize HashSet vs LinkedHashSet may greatly improve the performance of your code.

HashSet, a component of the Java Collections Framework, is a general-purpose set implementation. It saves elements using a hash table technique, which provides constant-time performance for fundamental operations like add, delete, and contain. If you want rapid retrieval and don't need a set sequence for your pieces, HashSet is your go-to option.

In contrast, LinkedHashSet extends HashSet and retains a predictable iteration sequence. It combines a hash table and a doubly linked list to ensure that entries are stored in the same order they were added. If you want to iterate through the elements in the order they were added, LinkedHashSet is the right choice.

Consider utilizing HashSet when you want the best speed for fundamental set operations and the order of elements is irrelevant. LinkedHashSet, with its ordered iteration, is useful when preserving insertion order is critical to your application logic.

To summarise, use HashSet for performance in fundamental operations and LinkedHashSet when you need a predictable iteration sequence. Understanding the distinctions between these two classes allows you to make educated decisions that improve the performance and maintainability of your Java code.