自写ArrayList中的大多数方法

package collection;

import java.util.Arrays;

public class NewList {
private Object[] array;
private int size;
public NewList()
{
this(10);
}
public NewList(int capacity)
{
if(capacity < 0)
{
try
{
throw new Exception();
}
catch(Exception e)
{
e.printStackTrace();
}
}
else
{
array = new Object[capacity];
}
}
public int size()
{
return size;
}

public static void main(String[] args) {
	// TODO Auto-generated method stub
	NewList lis = new NewList(4);
	Object[] obj = lis.toArray();
	lis.add("abc");   //往容器中丢对象
	lis.add("kkk");
	System.out.println(Arrays.toString(obj));   //打印对象
	System.out.println(lis.size());         //打印容器中有多少对象
	lis.add(0, "ooo");                      //指定位置插入对象
	System.out.println(Arrays.toString(obj));
	lis.set(1, "benda");                   //修改指定位置的值
	System.out.println(Arrays.toString(obj));
	System.out.println(lis.get(2));        //获得指定位置的值
	lis.remove(0);                         //删除指定位置的值
	System.out.println(Arrays.toString(obj));  
	
}
//数组扩容函数
public void Capacity_expansion()
{
	if(size == array.length)
	{
		Object[] newarray = new Object[size * 2];
		for(int i = 0; i < array.length; i++)
		{
			newarray[i] = array[i];
		}
		array = newarray;
		
	}
}
//add(Object element)方法
public void add(Object element)
{
	Capacity_expansion();
	 array[size] = element;  //赋值
	 size++;
}
public void RangCheck(int index)
{
	if(index >= size || index < 0)
	{
		try
		{
			throw new Exception();
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
	}
}
//add(int index, Object element)方法
public void add(int index, Object element)
{
	RangCheck(index);
	Capacity_expansion();
	System.arraycopy(array, index, array, index + 1, size - index);
	array[index] = element;
	size++;
}
//get(int index)方法
public Object get(int index)
{
	RangCheck(index);
	return array[index];
}
//remove(int index)方法
public Object remove(int index)
{
	RangCheck(index);
	Object oldvalue = array[index];
	System.arraycopy(array, index + 1, array, index, size - index - 1);
	array[size] = null;
	size--;
	return oldvalue;	
}
//set(int index, Object element)方法
public void set(int index, Object element)
{
	RangCheck(index);
	array[index] = element;
}
//Object[] toArray()方法
public Object[] toArray()
{
	return array;
}

}
//基本编译显示结果