Help modify a simple java code program, OVERLOADED HELP

import java.util.*; 
class myCust { 
void rect(int a,int b) {
 int result = a*b; System.out.println(result); 
}
 void rect(double a,double b) { 
double result = a*b; System.out.println(result); 
} }
 class rectarea { public static void main(String[] args) 
{ 
myCust zo = new myCust();
 Scanner input= new Scanner(System.in);
 System.out.println("Please enter values:"); 
//I need to change this to accept 1 for business 2 for residence and then have name of person then name then
//phone number accepted by input?
 double a = input.nextDouble(); 
double b = input.nextDouble(); 
zo.rect(a,b);

//or I can use just a very basic overloaded program, CONFUSED with ... in the syntax

public class genericId {
    ...
    public void genId(String s) {
        ...
    }
    public void genId(int i) {
        ...
    }
    public void genId(double f) {
        ...
    }
    public void genId(int i, double f) {
        ...
    }
}