Thread: Using Comparable in Binary Search

So I have written some code which tells whether a certain Integer is within a list of integers. I tried to do this with a comparable type instead of 'integer' type, but I realised that this wouldn't work as we could have say a String and Integer in the same list. I want to be able to have comparables of all the same type, but not limited to just Integers... Does anyone know how I could do this? I'm not very confident with using interfaces as input parameters. This is my code:

package Recursion;
 
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
 
public class BinarySearch {
	// Takes in a sorted list (ascending order) of comparable objects 
	// and finds whether a certain object is in that list using binary 
	// search method.
 
	public static void main(String[] args){
		ArrayList<Integer> l = new ArrayList<Integer>();
		l.add(3);
		l.add(10);
		l.add(30);
		l.add(502);
		System.out.println(l);
		Scanner s = new Scanner(System.in);
		while(s.hasNextInt()){
			int n = s.nextInt();
			System.out.print(BinarySearch.search(l, n));
		}
	}
 
	//Check whether something is in the list
	public static boolean search(List<Integer> al, Integer c){
		//Current one we are looking at
		Integer pivot = al.get(al.size()/2);
 
		if (c.equals(pivot)){
			return true;
		} else if (c.compareTo(pivot) == -1){
			if (al.size()/2 == 0){ //if our pivot is the first value in the sorted list
				return false; // no more to see		
			} else {
				return search(al.subList(0,al.size()/2),c);
			}
		} else {
			if(al.size()/2 == 0){
				return false;
			} else {
			return search(al.subList(al.size()/2,al.size()),c); 
			}
		}
 
	}
 
}

I understand that I have to implement the interface to use a data type as a 'comparable'.. however this is not my issue. The issue is that I want my list to contain any type which implements comparable, but I want it to be so only one type can be in the list at a time. For example, I could use this code to make and search a list of Integers as they are comparable, or a list of Strings, but I dont want to be able to have integers and strings in the same list.

By making the input list type List<Comparable> this doesnt force the elements to be of one comparable type, but various types.