http://www.verejava.com/?id=17159894213940

/**
     * 注意:        
    1. ArrayList 是按照添加的顺序,有序先进先出的.
    2. ArrayList 可以添加重复元素
    3. ArrayList 也可以添加 空值 null
    4. ArrayList 内部是以对象数组 实现的
*/
import java.util.ArrayList;
import java.util.List;

public class Test {

    public static void main(String[] args) {
        List list = new ArrayList();
        //        boolean     add(Object o)
        list.add(1);
        list.add(1);
        list.add(null);
        list.add(2.5);
        list.add(true);
        list.add("王强");
        list.add('A');
        list.add(new Cat("波斯猫"));
        //
        //        Object     get(int index) 
        Object wangqiang = list.get(3);
        System.out.println(wangqiang);
        //        int     size()    
        System.out.println(list.size());
        //
        //        boolean     contains(Object o) 
        System.out.println(list.contains("王强"));
        //        boolean     isEmpty()    
        System.out.println(list.isEmpty());
        //
        //        set(int index, Object element)
        list.set(4, 'B');
        System.out.println(list.get(4));
        //
        //遍历集合打印所以元素
        for (int i = 0; i < list.size(); i++) {
            Object obj = list.get(i);
            System.out.print(obj + ",");
        }
        //        boolean     remove(int index)    
        list.remove(4);
        System.out.println("");
        for (int i = 0; i < list.size(); i++) {
            Object obj = list.get(i);
            System.out.print(obj + ",");
        }
        //        void     clear()    
        list.clear();
        System.out.println("");
        System.out.println(list.size());
        System.out.println(list.isEmpty());
        for (int i = 0; i < list.size(); i++) {
            Object obj = list.get(i);
            System.out.print(obj + ",");
        }
    }
}

public class Cat {
    
    private String name;

    public Cat(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String toString() {
        return name;
    }
}

http://www.verejava.com/?id=17159894213940