静态变量的导入以及集合的运用

package com.jtest;
//静态变量的导入
import static java.lang.Math.*;
import static java.lang.System.*;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class StaticTest {
    public static void main(String[] args) {
// TODO Auto-generated method stub
        out.print(abs(-9));
}
    public void test(){
     Integer i=9;//自动装箱
     int j=i;//自动坼箱
     List<Integer> l=new ArrayList<Integer>();
     l.add(1);
     l.add(2);//自动装箱
     l.add(4);
     l.add(5);
     System.out.println("=====加强for循环取值=====");
     for(Integer c:l){
      out.print(c+"\n");
     }
     System.out.println("----用迭代器取值------");
     Iterator<Integer> iterator=l.iterator();
     while(iterator.hasNext()){
      Integer in=iterator.next();
      out.print(in+"\n");