Binary search from https://stackoverflow.com/q/59054704

BinarySearchExample.java

// https://stackoverflow.com/q/59054704/243245
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class BinarySearchExample {
    public static void main( String[] args )
            throws IOException
    {
        LookupTable table = new LookupTable();
        table.read(new Scanner(new File("input.txt")));

        Scanner in = new Scanner(System.in);
        System.out.println("Enter item name to get price:");
        String n = in.nextLine();
        System.out.println( table.lookup_by_item(n) + "\n");
    }
}

class LookupTable {
    private ArrayList<Item> Item_key;

    public LookupTable() {

        Item_key = new ArrayList<Item>();

    }

    public void read(Scanner in) {

        String k = null, v = null;

        while (in.hasNextLine()) {
            k = in.nextLine();
            v = in.nextLine();
            Item_key.add(new Item(k, v));
            //System.out.println(k);
            //System.out.println(v);
        }
    }

    public String lookup_by_item(String n) {
        Collections.sort(Item_key);

        int index_found = Collections.binarySearch(Item_key, new Item(n, null));
        System.out.println(index_found);
        String itemn = "";

        if (index_found >= 0) {

            itemn = Item_key.get(index_found).getValue();

        }
        return itemn;
    }
}

class Item implements Comparable<Item> {
    public String key;
    public String value;

    public Item(String k, String v) {
        key = k;
        value = v;
    }

    public String getKey() {
        return key;
    }


    public String getValue() {
        return value;
    }

    public int compareTo(Item otherObject) {
        Item other = (Item) otherObject;
        return key.compareTo(other.key);
    }
}

input.txt

Flat White
4.05
Cappuccino
4.45
Latte
4.45
Americano
3.35
Iced Coffee
3.25
Cold Brew
3.75