double represents double-precision numbers. double is 64-bit width and its range is from 4.9e-324 to 1.8e+308 approximately.
Here is a program that uses double variables to compute the area of a circle:
public class Main {
public static void main(String args[]) {
double pi, r, a;
r = 10.8888; // radius of circle
pi = 3.1415926; // pi, approximately
a = pi * r * r;
System.out.println("Area of circle is " + a);
}
}
The output:
Area of circle is 372.4859596381597