Here is the problem I am working on: Write a class encapsulating the concept of a Student, assuming that a student has the following attributes: last name, first name, id, array of grades. Include a constructor, the accessors and mutators, and method toString. Also code the following methods: one returning the GPA using the array of grades (assuming each grade represents a course grade and all courses have the same number of credit hours) and a method to add a course grade to the array of grades (this means creating a larger array). Write a client class to test all your methods.

Here is the code I have written:

(1st java file, Student.java)

import java.util.Arrays;

import java.util.Scanner;

public class Student

{

public String lastName;

public String firstName;

public int id;

public double grades[]=new double[4];

public double gpa;

//Constructor to initialize data members of the class

public Student(String lastName, String firstName, int id, double[] grades){

super();

this.lastName = lastName;

this.firstName = firstName;

this.id = id;

this.grades = grades;

}

//default constructor

public Student(){

}

//set and get methods

public void setLastName (String lastName){this.lastName = lastName;}

public String getLastName () {return lastName;}

public void setFirstName (String firstName){this.firstName = firstName;}

public String getFirstName () {return firstName;}

public void setId (int id) {this.id = id;}

public int getId () {return id;}

public void setGrades (double[] grades) {this.grades = grades;}

public double[] getGrades () {return grades;}

public void setGpa (double gpa) {this.gpa = gpa;}

public double gpa () {return gpa;}

@Override

public String toString() {

return "Student: Last Name is " + lastName + ", First Name is " + firstName + ", Student ID number is " + id + ", Grades are "+ Arrays.toString(grades);

}

//method to return the GPA using the array of grades

public static double calcGpa(double[] grades){

double gpa = 0;

for (int i=0;i

gpa += grades[i];

}

gpa = (gpa/grades.length);

return gpa;

}

//method to add a new grade to the array of grades

public static double[] addGrade (double[] grades){

double newEntry;

System.out.println ("Enter the value of the new grade.");

Scanner in=new Scanner(System.in);

newEntry = in.nextDouble();

double[] newGrades = new double[grades.length+1];

for (int i=0;i

newGrades[i]=grades[i];

}

newGrades[newGrades.length-1]=newEntry;

grades=newGrades;

return grades;

}

}

(2nd java file, TestStudent.java)

public class TestStudent{

//Create a student object.

public static void main(String[] args) {

Student a1 = new Student();

double[] grades = {4.0,3.0,2.0,1.0};

a1.setGrades(grades);

a1.setLastName("Smith");

a1.setFirstName("Jenny");

a1.setId(8675309);

System.out.println(a1.toString());

//Test calcGPA

double gpa=calcGpa(grades[]);

System.out.println("Current GPA is " +gpa);

//Test addGrade

double[] addGrade=grades;

for (int i=0;i

System.out.print(grades[i]+" ");

}

}

}

When trying to compile the TestStudent.java file, I get the erro "TestStudent.java:19: error '.class' expected double gpa=calcGpa(grades[]);

Any help with solving this would be highly appreciated, and my apologies for the bad formatting.