Inheritance student, undergrad and gradstudent code : For a class project I was asked to create three codes. First the student class containing 3 Parameters. Name(String), TestScores( int array), Grade(String). An Empty Constructor- sets the Name and Grade to empty Strings. The TestScores Array will be created with 3 zeros. Another Constructor(String n, int[] tests, String g)- This will set the name, testScores, and grade. Three methods getName()- Returns the Name, getGrade()- Returns the Grade, setGrade()- Sets the Grade, and getTestAverage()- returns the average of the test scores. The method computeGrade()-If the average is greater than or equal to 65, the grade is a "Pass". Otherwise it is a "Fail". The second class is called UnderGrad- This class is a subclass of Student. We had to create an Empty Constructor and another Constructor(String n, int[] tests, String g).We were instructed to override the computeGrade() method so that an UnderGrad() student must get a 70 or higher to pass. The third class is the GradStudent- is a subclass of Student. We have to create 1 instance variable- int MyGradID. An empty Constructor Remember to call super and set the ID to 0. And another constructor(String n, int[] tests, String g, int id)- Remember to call the super constructor and set ID. We had to write the method getId()-returns the ID number. Again we needed to override the computeGrade() method-If if the average is greater than or equal to 65, the grade is a "Pass". Otherwise it is a "Fail". If the test average is higher than 90, the grade should be "Pass with distinction".
I have great difficulty with this task. I attached the GradStudent code. can you find the errors please. I don't fully understand how to override the superclass private instance variables.

           public class GradStudent extends Student
          {
         private int MyGradID;
  
          public void GradStudent()
          {
           super();
           MyGradID= 0;
          }
          public void GradStudent(String n, int[]tests,String g, int id)
         {
          super(n,tests,g);
          MyGradId = id;
         }
          public int getId()
        {
         return MyGradId; 
        }
         public void computeGrade()
        {
        if(testScores.getTestAverage>=65)
        {
          super.setGrade("Pass");
         }
          else if (testScores.getTestAverage>90)
         {
          grade = "Pass with distinction";
         }
         }