User input for creating objects

I'm trying to code something to create a specific object if it matches the values that the user Inputs.

For example:

suppose I have Person class and Car class

public class Person
{
    private int x, y ,z;
    private String str;

    //Constructors etc
} 
public class Car
{
    private int x,y,z;
    private double doub;

    //Constructors etc
}

The user is asked to input 4 different values. The first three fields of Person and Car are the same but if the 4th value is a String or double, the program should create the matching object.

public class Input
{
     public static void main (String args[])
     {
         int x,y,z;
         ?? other; //how do i declare if its either a double or string

         Scanner input = new SCanner(System.in);
         x = input.nextInt();
         // y, z input
         other = input.??? //String or double

         //Create matching object
     }
}

How do i go about this?