cannot be cast to java.lang.Comparable

I am trying to sort the array by name or price depending on input. It is saying that the method sort is not applicable and that it cannot be cast. I have looked and can not figure it out or find information on it that is helpful.

This is for a homework assignment, so any type of brief help is welcome.

/*
 
 */

public class Item {
	public static String name;
	public static double price;
	
	public void setName(String someItem){
		name = someItem;
	}
	public void setPrice(double somePrice){
		price = somePrice;
	}
	
	public String getName() {
		return name;
	}
	public double getPrice() {
		return price;
	}
}

/*

 */
import java.util.*;
public class CoffeeDriver {
	public static Item[] arr = new Item[5];
	
	public static void sortName(){
		Arrays.sort(arr, Item.name);
	}
	
	public static void sortPrice(){
		Arrays.sort(arr, Item.price);
	}
	

	public static void main (String[] args){
		@SuppressWarnings("resource")
		Scanner input = new Scanner(System.in);
		
		arr[0] = new Item();	
			arr[0].setName("Coffee");
			arr[0].setPrice(1.00);
		arr[1] = new Item();
			arr[1].setName("Water");
			arr[1].setPrice(2.00);
		arr[2] = new Item();
			arr[2].setName("Milk");
			arr[2].setPrice(1.50);
		arr[3] = new Item();
			arr[3].setName("Bagel");
			arr[3].setPrice(1.25);
		arr[4] = new Item();
			arr[4].setName("Donut");
			arr[4].setPrice(0.75);
			
		boolean exit = false;
		
		do{
			System.out.println("Welcome to Wings Coffee Shop. We have a great list of items on our menu.\n Would you like to see these items sorted by name or by price?\n 1 for name, 2 for price, 3 to exit ");
			int choice = input.nextInt();
			
			switch(choice) {
			case 1:
				sortName();
				break;
			case 2:
				sortPrice();
				break;
			case 3:
				exit = true;
				break;
			default:
				System.out.println("Invalid");
			}
			
		}
		while(!exit);
		
	}

}