二分法查找ArrayList中的元素

import java.util.ArrayList;
import java.util.Collections;

public class BinarySearchForArrayList {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    ArrayList arrayList = new ArrayList();
     
    arrayList.add("1");
    arrayList.add("4");
    arrayList.add("2");
    arrayList.add("5");
    arrayList.add("3");

    Collections.sort(arrayList);
    System.out.println("Sorted ArrayList contains : " + arrayList);
   
    //search an element using binarySearch method of Collections class
    int index = Collections.binarySearch(arrayList,"4");
   
    System.out.println("Element found at : " + index);
}

}

Console：
Sorted ArrayList contains : [1, 2, 3, 4, 5]
Element found at : 3