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How to Use Pairs in Java

Version 7 of Java brought the “pair” class, which made it simple to return two items from a method. Although writing more code to achieve the same goal is absolutely possible, Pairs in Java adopting this pre-existing class will save time and effort compared to creating your own workaround.

Holding a pair of values is the primary function of the Java pair class. Though keys mapped to values are particularly not mentioned, this simply refers to pairs of values that are stored together, which may sound similar to a HashMap. Check out the Java online training to learn more.

This class may be useful in a variety of scenarios where a method requires two return values, such as when working with coordinates. 

Value is stored in key-value pairs via the Java Pair class. It helps to obtain two values. Tuples are the name for this key-value pair.

When we want a method to return two values, the pairs come in handy. For instance, let’s say we want to print a number together with its square root and we have a way for doing that. As a result, we can publish the result as both its square root and a mixture of digits.

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As of Java 8, Java comes with an integrated Pair class.

How to Use Pairs in Java

In Java, what do pairs do?

In Java, pairs serve as a means of maintaining value pairs together, as their name implies. It is comparable to a hashmap in certain aspects, including how values are retrieved through methods. The main distinction is that here, rather than a key being directly mapped to a value, it might refer to any two abstract values.

Then, to see if these paired values are equal, they can be compared to other paired values. This indicates a comparison of the values in the pairs. The outcome then depends on whether or not both sets of values are the same, returning either a true or false (boolean) result.

With applications ranging from calculators to video games, this can be quite helpful for any website that performs calculations on a two-dimensional grid. This class is useful for anything that needs (x,y) coordinates on a two-dimensional plane.

Given that a mouse is just a point on a two-dimensional plane, pairs can even assist in keeping track of it on the screen.

Java offers a Pair class, available from Java 8, for storing values in key pair combinations. We must utilise the parameterized constructor offered by the javafx.util.Pair class in order to store the value in a pair combination.

When storing the value in a tree data structure, the Pair class comes in handy. Using the Pair class makes it simple to pass values from one node to another during recursive operations on a tree data structure. Up to that node, these values can represent the minimum and maximum node values. This would stop the pointer from constantly going back to particular codes.

How to Use Pairs in Java

Maps are used in Java to store values in the format of key pair combinations. They treat the values as a single object and store them as tuples.

Types of Pair Classes

Java has two different kinds of Pair classes, which are as follows:

  • Immutable Pair Class: These classes prevent an object’s value from changing once it has been defined; hence, we are unable to modify defined values using the setters function. If the value is defined, it usually won’t change.
  • Mutable Pair Class: We can change the value of a mutable class at any point during the program. The getters and setters methods allow us to access and modify an object’s value. Even if we defined the values at the beginning of the program, we may change them later on. The object value can be set and accessed using the pair.setValue(a,b) and pair.getValue() methods.

Why do We Need Pair Class

To retrieve the value in a key pair combination, utilise the pair class. Stated differently, the methods in the pair class return two values together. We may utilise the Pair class for a variety of reasons.

A few situations in which we must utilise the Pair class are as follows:

  • Let’s say we wish to provide more than one value. Although we may accomplish this by utilising data structures like Arrays and HashMaps, it might become challenging to return both of them when working with a cluster of variables at once. The Pair class will come in extremely handy in these situations.
  • The Pair class makes it simple to display the result of a mathematical operation combined with the number that was calculated.
  • In the event that we wish to work with a tree data structure.

How to Use Pairs in Java

It would be easy to go back to the previous coordinate example if you so desired. For instance, suppose a code records the coordinates (2, 1) and (4, 2) in pair class instances. Then, in order to do some simple maths, it removes those values once more.

  • The pairs class should be imported first using the following line of code. If you try to reference this class without this, Java will scream at you since it doesn’t comprehend what you’re talking about.
  • The next step is to use the required data to generate instances of the pair class. Coordinates in this instance might be integers. It is advisable to use the Float data type in this case since the midpoint may also be a decimal number. It is also used to avoid loss of precision during calculations.
  • You may raise an eyebrow when you take the values out of the pairs. This format seems a lot like the HashMap data structure, doesn’t it?
  • Now, use these coordinates to find the middle. you put it simply, multiplying the result by two and adding the related coordinates is how you accomplish this.
  • After determining the midpoints of x and y, the solution should be saved in a pair object.
  • Lastly, check that the maths is correct by displaying the result in your terminal. You ought to receive a score of 3.0 and 1.5 from this example.


In conclusion, pair classes are a great way to increase the effectiveness of your code. Storing the value in a tree data structure is one practical application of the Pair class. We can modify our classes or use the built-in Pair classes. They will be highly beneficial if utilized correctly. To learn more, check out our java course online certification.  

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