Collections 工具类常用方法

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

public class demon1 {
    /*
     * A:Collections类概述
    * 针对集合操作 的工具类
    * B:Collections成员方法
      * 
        public static <T> void sort(List<T> list)
        public static <T> int binarySearch(List<?> list,T key)
        public static <T> T max(Collection<?> coll)
        public static void reverse(List<?> list)
        public static void shuffle(List<?> list)
     */
    public static void main(String[] args) {
        ArrayList<String> a1 = new ArrayList<>();
        a1.add("a");
        a1.add("c");
        a1.add("d");
        a1.add("b");
        System.out.println(a1);
        Collections.sort(a1);
        System.out.println(a1);
        System.out.println(Collections.binarySearch(a1, "b"));
        Collections.reverse(a1);
        System.out.println(a1);
        Collections.shuffle(a1);
        System.out.println(a1);
        
    }

}