#    
## Overview

A **mutable pair** consists of two object elements. 

`MutablePair` is defined in the [Apache Commons Lang](https://commons.apache.org/proper/commons-lang/). The package has to be added to the classpath before `MutablePair` is used.

If Maven is used, add the following in the `dependencies` section of `pom.xml`.

```xml
<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
</dependency>
```

After the dependency above is imported, import the `MutablePair` class as follows.

```
import org.apache.commons.lang3.tuple.MutablePair;
```

> Note: There are *setters* in this class, as the data structure is mutable in nature.

The two object elements in the `MutablePair` are named `left` and `right`. Therefore, the objects will be referred to as `left` and `right` for any operations on the data structure.

#    
## How to create a `MutablePair` object

There are several ways to create a `MutablePair` object. 

## Use the constructor

The constructor of the `MutablePair` class accepts the `left` and `right` elements as parameters.

```java
MutablePair<String, String> mutablePair =  new MutablePair<>("leftValue", "rightValue");
```

## Use the of() method

The **`of(left, right)` method** can be used to create an object of the `MutablePair` class. It accepts the `left` and `right` elements as parameters.

```java
MutablePair<String, String> mutablePair =  MutablePair.of("leftValue", "rightValue");
```


#    
## How to set elements of the `MutablePair` object

### Set the `left` element

The value of the `left` element can be set using the `setLeft()` method.

```java
mutablePair.setLeft("leftValue");
```

### Set the `right` element

The value of the right element can be set using the `setRight()` method.

```java
mutablePair.setRight("rightValue");
```

#   
## How to access the elements of the `MutablePair` object

### Access the `left` element

The `left` element can be accessed as a property or by the `getLeft()` method.

```java
String leftElement = mutablePair.left;
// OR
String leftElement = mutablePair.getLeft();
```

### Access the `right` element

The `right` element can be accessed as a property or by the `getRight()` method.

```java
String rightElement = mutablePair.right;
// OR
String rightElement = mutablePair.getRight();
```

#   
## Code

In the example below, a `MutablePair` object is created without the `left` and `right` values. Then, the elements of the object are set using the setters, and the elements are printed using the getters.

import org.apache.commons.lang3.tuple.MutablePair;

public class Main {

    public static void main(String[] args){
        MutablePair<String, String> mutablePair = new MutablePair<>();
        mutablePair.setLeft("leftValue");
        mutablePair.setRight("rightValue");
        System.out.println("Left Element - " + mutablePair.getLeft());
        System.out.println("Right Element - " + mutablePair.getRight());

    }
}

What is a MutablePair in Java?

A MutablePair in Java, from Apache Commons Lang, stores two mutable object elements named left and right, and can be created, modified, and accessed using constructors, methods.

What is a MutablePair in Java?

Overview

How to create a MutablePair object

Use the constructor

Use the of() method

How to set elements of the MutablePair object

Set the left element

Set the right element

How to access the elements of the MutablePair object

Access the left element

Access the right element

Code

How to create a `MutablePair` object

How to set elements of the `MutablePair` object

Set the `left` element

Set the `right` element

How to access the elements of the `MutablePair` object

Access the `left` element

Access the `right` element