Examples Of Conversion Between An Array And A Set In Java

Examples Of Conversion Between An Array And A Set In Java



Here are some examples of how to carry out the conversion of an array to a set; it is very important to keep in mind that sets only include unique items to prevent duplicate elements from adding to the Set in the conversion process.

Array: An array is a collection of variables that are of similar types and also go by the same name. Depending on how one defines the array, it can contain both objects of a class and basic data types. The actual values for the primitive data types are put together in the form of a group with corresponding memory regions. The real objects that comprise objects belonging to a class are then kept in the heap section. Set in Java provides an extension to Java. Util.Collection interface. It is also known to be a component of Java. util package. It prohibits the usage of some sort of duplicate items and can only provide support for a single null element at the maximum limit. The following are some of the key characteristics when it comes to the Java Set interface:

  • Duplicate values cannot be put in storage in the random collection of objects that makes up to become the set interface.
  • The position of element insertion, as well as deletion, cannot have an exertion of control through the Java Set.
  • In essence, HashSet, LinkedHashSet, or TreeSet implement Set (all of these belong to the categorization of sorted representation).
  • To improve the use of this interface, Set gets an offer of several ways for adding, removing, clearing, sizing, and other functions as well.

The conversion process is a cakewalk once the user gets an idea about Arrays.asList () and its usage. After that, you can use a different conversion constructor provided by the Collection class for converting one collection to another, like “List to Set” and many more. 

If you wish to convert an Array to a Collection in Java, it is important to follow these steps:

  • Make use of the Arrays.asList() function to convert an array to a list.
  • Add it, particularly to your collection.

And here are the steps you can follow to make a change a Java Array into a Set:

  • Change an array to the form of a list.
  • Copy these particular items from the present List to create a Set.

Lastly, steps for the conversion of an array into a list in Java include the following:

Arrays.asList () leads to the return of a list; hence there is no further conversion.

When you try the process of addition or removal when it comes to this List, you will get “Exception in thread “main” Java.lang.unsupported operation exception”.

To gain complete knowledge about Arrays and sets in Java, Java Training helps to a great extent.

An Insight on Arrays in Java

An array is considered to be a container object that is responsible for the storage of a fixed number of single-type values. The length of an array is determined when there is an execution of its construction. Its length is set when the creation takes place. One must have previously seen the examples of arrays in the main function when it comes to the “Hello World!” program. This section delves deeper into the concept of arrays. 

An array’s items are called elements, and each element is accessible by employing its numbering index. The system starts with 0. As a result, the 9th element, for instance, would be accessible at index 8. In practice, rather than making a write-up of each line separately, you would generally use one of the various looping constructs to carry out the iteration process with the help of each element of the array. There are a lot of different demonstrations when it comes to array syntax.

Declaring a Variable for the reference to an Array

An array declaration, like declarations when it comes to sorts of variables, consists of two components: the array’s type and name. The array’s type gets its representation in type[], where type is considered a data type of the items included; the brackets signify certain special symbols indicating that this particular variable contains an array. The array’s size does not constitute a part of its type (which is why the brackets are found to be empty). 

The name of an array may be whatever the user wants it to be as long as it respects the rules and standards that one can find in the naming section. The declaration, just like other types of variables, does not end up building an array; it only informs the compiler that this variable will store an array of the given type.

Array Manipulations

Arrays are considered to be powerful as well as insightful concepts that are put to use in programming. With the help of Java SE, one can get all the methods necessary for the performance of some of the most sought-after manipulations related to arrays. If we take the example of ArrayCopyDemo, we see that it uses the array copy technique that belongs to the System class instead of carrying out the process of manual iteration with the help of the elements of the source array and using the placement of each one of them into the position of the destination array. This is carried out behind the scenes and enables the developers to use only one line of code for calling the method. 

Set in Java

The set interface is provided in the extension to the Collection interface and is included in Java. Util the package as well. One can consider it an unordered collection of objects that cannot store duplicate values. For starters, it is a mathematical set implementation interface. This interface inherits the Collection interface’s methods, and it also leads to an addition of a feature that prevents the insertion when it comes to duplicate elements. SortedSet and NavigableSet are two distinct interfaces that cause the expansion of the set implementation.

Because a set is not in charge of its insertion order, the navigable set interface offers an implementation to carry out the traversing of the Set. The navigable Set is implemented by a TreeSet, which is considered an implementation of a self-balancing tree. As a result, this interface allows a person to undergo traversing across this tree.

Some properties relating to Set

– A Set is a Collection that consists of absolutely no duplicate components. It is a representation, in a way, of mathematical set abstraction.

– The Set interface only does the inheritance of the Collection methods, and it also adds the limitation that duplicate elements are not permitted.

– Set additionally strengthens the contract on the behaviour when it comes to the equals and hashCode operations, thus allowing Set instances to be meaningfully compared even if any kind of difference exists in implementation types.

Carrying out operations on the Set Interface

There are a lot of basic maths operations, like union, difference, and intersection, that can be carried out on Set. 

Let us consider that we have two sets that is set1 consisting of [22, 45, 33, 66, 55, 34, 77] and then there is set2= [33, 2, 82, 45, 3, 12, 55]. These are the operations that can take place on the Set:

  • Intersection: The intersection operation carries out the process of returning all elements that appear in both sets. Set1 and set2 will see a cross at [33, 45, 55].
  • Union: The union operation returns all of the elements of sets 1 and 2 in a single set, which might be set1 or set2. The sum of sets 1 and 2 results in [2, 3, 12, 22, 33, 34, 45, 55, 66, 77, 83].
  • Difference: The difference operation carries out the process of removing any values that one can find in another set. The difference that we will get between sets 1 and 2 is [66, 34, 22, 77].

In Set, the union is performed by making use of the addAll() method, the intersection is then performed using the retainAll() method and lastly, the difference is performed by making use of the removeAll() method. 


As discussed in the points mentioned above, there are three implementations in Java, namely HashSet, TreeSet, and LinkedHashSet. One can use any of the three to carry out the conversion process. These processes are fast, and they also offer constant-time operations. 

Author Bio:

I am Korra Shailaja, Working as a Digital Marketing professional & Content writer in MindMajix Online Training. I Have good experience in handling technical content writing and aspire to learn new things to grow professionally. I am an expert in delivering content on the market demanding technologies like Mulesoft Training, Dell Boomi Tutorial, Elasticsearch Course, Fortinet Course, PostgreSQL Training, Splunk, Success Factor, Denodo, etc.


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