java.lang.Math.atan2() in Java

atan2() is an inbuilt method in Java that is used to return the theta component from the polar coordinate. The atan2() method returns a numeric value between –and representing the angle of a (x, y) point and the positive x-axis. It is the counterclockwise angle, measured in radian, between the positive X-axis, and the point (x, y). 
Syntax :

Math.atan2(double y, double x)
where, x and y are X and Y coordinates in double data type.

Returns :
It returns a double value. The double value is from polar coordinate (r, theta). 
Example: Program demonstrating the atan2() method 

Java

// Java program for implementation of
// atan2() method
import java.util.*;
class GFG {

    // Driver Code
    public static void main(String args[])
    {

        // X and Y coordinates
        double x = 90.0;
        double y = 15.0;

        // theta value from polar coordinate (r, theta)
        double theta = Math.atan2(y, x);

        System.out.println(theta);
    }
}

Output

0.16514867741462683