2、　　声明测试类TestStudent完成对多态性的测试：（1）在主方法中声明Student类的数组（含五个元素）。（2）生成五个对象存入数组，其中三个Student类的对象、一个StudentXW类的对象、一个StudentBZ类的对象。（3）将方法testScore()发送给数组的每一个元素，输出结果，并分析具体执行的是哪一个类中的方法。-2, statement completion of testing polymorphisms TestStudent type of test: (1) a statement in the main method of Student class array (including the five elements). (2) to generate the object into an array of five, three of which the object of type Student, a category StudentXW object, the object of a category StudentBZ. (3) methods testScore () sent to each element of the array, the output results and analysis of the specific implementation of a class in which the method.