Java Example - Get the index value of a vector element

/*
 author by w3cschool.cc
 Main.java
 */import java.util.Collections;import java.util.Vector;public class Main {
   public static void main(String[] args) {
      Vector v = new Vector();
      v.add("X");
      v.add("M");
      v.add("D");
      v.add("A");
      v.add("O");
      Collections.sort(v);
      System.out.println(v);
      int index = Collections.binarySearch(v, "D");
      System.out.println("元素索引值为 : " + index);
   }}