Quadratic Roots

/* This program solves the quadratic equations(ax^2+bx+c)
and finds th values of x when user provides th value of a,b and c*/
import java.io.*;
class Quadratic
{
 BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
 double A,B,C,R1,R2,D;
 public void calcRoots() throws IOException
 {
     System.out.println("Enter value of A");
     A=Double.parseDouble(br.readLine());
     System.out.println("Enter value of B");
     B=Double.parseDouble(br.readLine());
     System.out.println("Enter value of C");
     C=Double.parseDouble(br.readLine());
     D=(B*B)-(4*A*C);
     if(D>=0)
     {
         R1=(-B+Math.sqrt(D))/(2*A);
         R2=(-B-Math.sqrt(D))/(2*A);
         System.out.println("Roots are = "+R1+"  "+R2);
     }
     else
         System.out.println("Roots are imaginary");
 }
 public static void main(String args[])
{
Quadratic q=new Quadratic();
q.calcRoots();
}
}