importjava.util.*;publicclassCollectionTest{publicstaticvoidmain(String[]args){//1.创建集合Collectionc=newArrayList();//2.向集合中添加元素c.add(1);//jdk1.5之后的自动装箱，c.add(newInteger(10));Objecto=newObject();c.add(o);//collection只能存储单个元素，并且存储的元素是引用数据类型。Customercustomer=newCustomer("张三",30);c.add(customer);//3.获取元素的个数System.out.println(c.size());//4.判断集合是否为空？System.out.println(c.isEmpty());//5.将集合转换成oject类型的数组Object[]orray=c.toArray();for(inti=0;i<orray.length;i++){System.out.println(orray[i]);//对于Customer类需要重写toString方法。}//6.清空c.clear();System.out.println(c.size());}}publicclassCustomer{privateStringname;privateintage;publicStringgetName(){returnname;}publicvoidsetName(Stringname){this.name=name;}publicintgetAge(){returnage;}publicvoidsetAge(intage){this.age=age;}publicCustomer(Stringname,intage){super();this.name=name;this.age=age;}publicCustomer(){}//重写Customer的toString()方法publicStringtoString(){return"name="+name+""+"age="+age;}}