Object类可以接受引用类型

public class ObjectTest{
    public static void main(String args[]){
        Object obj = new int[] {1,2,3} ;
        System.out.print(obj) ;
        if(obj instanceof int []){
            int data [] = (int []) obj ;
            for(int x = 0 ; x < data.length ; x++){
                System.out.println(data[x]) ;
            }
        }
    }
}

interface A{
    public void funA() ;
}
class B implements A{   
    public void funA(){
        System.out.println("Hello world") ;
     }
}
public class ObjectTest{
    public static void main(String args[]){
        A a = new B() ;
        Object obj = a ;
        A t = (A) obj ;
        t.funA() ;
    }
}