package java_test;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
class clearListDemo{//清除list
public void clearList(){
List<String> list=new ArrayList<String>();
list.add("a");
boolean e=list.isEmpty();
System.out.println(e);
list.clear();//清除list里的所有元素
boolean m=list.isEmpty();
System.out.println(m);
System.out.println(list);
}
public void sortList(){//list排序
List<String> list=new ArrayList<String>();
list.add("d");
list.add("c");
list.add("a");
Collections.sort(list);//集合排序,升序排序
System.out.println(list);
}
}
public class arrayToArrayListDemo {
public static void main(String[] args) {
Integer [] i=new Integer[]{1,2,3};
List<Integer> t=Arrays.asList(i);
List<Integer> list =new ArrayList<>(t);//将数组转换为ArrayList的正确方式
System.out.println(list);
clearListDemo c=new clearListDemo();
c.clearList();
c.sortList();
}
}