The calculation of distance is an important aspect of mathematics. The space between the two points present in a plane is referred to as the distance. The distance between two points must always be a positive value since the line segment that is responsible for joining the two points can never be negative.

In this write-up, we will describe a method for the calculation of distance between two points in Java.

**How to Evaluate the Distance Between Two Points in Java?**

In Mathematics, the line segment joining the two points on a plane is referred to as the distance between the two points. The 2D plane consists of four points. For a certain point, let’s suppose P contains two coordinates (x1, y1) and another point Q contains (x2, y2). The formula mentioned below calculates the distance between two points.

Let us save the distance or the output as PQ therefore the formula becomes:

It is commonly referred to as the “Euclidean distance” formula.

**Example 1: Calculation of Distance Between Two Points Using Math Library**

In the below-mentioned code Math class of Java is imported to use the square root function for the calculation of the distance.

```
//Import the Math Class
import java.lang.Math.*;
//Declare a Class to calculate the distance
class distance{
public static void main(String arg[])
{
//Enter the integer values
int a1,a2,b1,b2;
double d;
a1=5;
b1=6;
a2=4;
b2=9;
//The Math class has all the integer values for calculation.
d=Math.sqrt((a2-a1)*(a2-a1) + (b2-b1)*(b2-b1));
//The output is printed on the screen. System.out.println("DISTANCE BETWEEN TWO POINTS");
System.out.println("The distance between "+"("+a1+","+b1+") and "+"("+a2+","+b2+") is "+d);
}
}
```

In the above-mentioned Java code:

- The
**Math**class is imported for certain functions. - In the Main class, the “a” and “b” coordinates are declared.
- The
**sqrt()**function in the above code helps to determine the distance. - The
**println()**method prints the distance.

**Output**

In the output below, the distance between the two points that are (5,6) and (4,9) is printed on the screen.

**Example 2: User Input for Calculation of the Distance**

The code below implements the scanner package that is “**util.Scanner**” to obtain the user input and it outputs the distance between the entered inputs.

```
//Import Scanner package for user input.
import java.util.Scanner;
class distancetwo {
//Scanner class to get the user input
public static void main(String[] args) {
Scanner sa = new Scanner(System.in);
//Declare the integers for the points
int a1,a2,b1,b2,a,b;
//The distance is declared as double
double distance;
//Taking the input as an integer.
System.out.print("Enter a1 point: ");
a1 = sa.nextInt();
System.out.print("Enter b1 point: ");
b1 = sa.nextInt();
//Taking the input as an integer.
System.out.print("Enter a2 point: ");
a2 = sa.nextInt();
System.out.print("Enter b2 point: ");
b2 = sa.nextInt();
//Calculate the distance a = a2 - a1;
b = b2 - b1;
//The Math class for the sqrt function
distance = Math.sqrt(a * a + b * b);
//Print the result for the distance between two points.
System.out.println("Distance between two points = " + distance);
}
}
```

In the above code:

- The Scanner package is imported to take the user input.
- With the Main class, the integer values for the coordinates are declared.
- The
**double-type**variable stores the distance. - To get the user input the
**println()**method prompts a message on the screen. - The
**nextInt()**method in Java fetches the value of the next integer. - The calculation takes place in such a manner that the subtraction results for x coordinates that are a1 and a2 are saved in a and the same for the y coordinates saved in b.
- The
**sqrt()**function calculates the distance using the distance formula. - The
**println()**method declares the results.

**Output**

In the output depicted below, the integer values for the coordinates are entered and the distance is calculated using the** sqrt()** method of Java.

This sums up the topic discussion on the calculation of distance between two points in Java.

**Conclusion**

The distance between two points in Java is evaluated using the “Math.sqrt((a2-a1)*(a2-a1) + (b2-b1)*(b2-b1));” equation/formula. The stated formula is commonly referred to as the “Euclidean distance” formula. This write-up has elaborated on the implementation of the Math package to calculate the distance between two points on a plane in Java.