数组怎么强制类型转换

[谁学逆向工程]

import java.util.*;
public class demo
{
	public static void main(String[]args) 
	{
		ArrayList<xx> liaoguodi = new ArrayList<xx>();
		xx x1 = new xx();
		xx x2 = new xx();
		liaoguodi.add(x1);
		liaoguodi.add(x2);
		liaoguodi.remove(0);

		xx u9 = new xx();
		liaoguodi.set(0,u9);

		xx [] arr =  (xx[])liaoguodi.toArray();
		System.out.println( arr.length) ;	
	}
	
}

class xx//任意类型
{} 

[Vencc__]

ArrayList<XX> arrayList=new ArrayList(); arrayList.add(new XX()); arrayList.add(new XX()); XX[] xxs=new XX[arrayList.size()]; arrayList.toArray(xxs); System.out.println(xxs.length);