Integral cannot be resolved to a type 为何这个类型他都认不出来

Integral cannot be resolved to a type 为什么这个类型他都认不出来
public class t {

public static void main(String[] args) {

Integral n1=new Integral();
Integral n2=new Integral();
n1.f=9f;
n2.f=12f;
System.out.println("n1="+n1+" "+"n2="+n2);
n1=n2;
System.out.println("n1="+n1+" "+"n2="+n2);
n1.f=999f;
System.out.println("n1="+n1+" "+"n2="+n2);

}
}


这个小测试程序

------解决方案--------------------
Integer是java类库自带的类

这个Integral是哪来的真不知道