Would this work?

$//$ Base class Student

public class Student $\{$

$//$ Private attributes

$$ private String firstName;

$$ private String lastName;

$$ private long studentID;

$//$ Constructor to initialize all fields

$$ public Student$($String firstName, String lastName, long studentID$)\{$

$$ this.firstName $=$ firstName;

$$ this.lastName $=$ lastName;

$$ this.studentID $=$ studentID;

$\}$

$//$ Getter for first name

$$ public String getFirstName$()\{$

$$ return firstName;

$\}$

$//$ Setter for first name

$$ public void setFirstName$($String firstName$)\{$

$$ this.firstName $=$ firstName;

$\}$

$//$ Getter for last name

$$ public String getLastName$()\{$

$$ return lastName;

$\}$

$//$ Setter for last name

$$ public void setLastName$($String lastName$)\{$

$$ this.lastName $=$ lastName;

$\}$

$//$ Getter for student ID

$$ public long getStudentID$()\{$

$$ return studentID;

$\}$

$//$ Setter for student ID

$$ public void setStudentID$($long studentID$)\{$

$$ this.studentID $=$ studentID;

$\}$

$//$ Method to compare two students based on student ID

$$ public boolean equals$($Student otherStudent$)\{$

$$ return this.studentID $==$ otherStudent.studentID;

$\}$

$//$ Method to report grade $($prints a message, meant to be overridden in child classes$)$

$$ public void reportGrade$()\{$

$$ System.out.println$("$There is no grade here."$)$;

$\}$

$//$ Method to display student information

$$ public void displayStudentInfo$()\{$

$$ System.out.println$("$Student Name: $"+$ firstName $+""+$ lastName$)$;

$$ System.out.println$("$Student ID: $"+$ studentID$)$;

$\}$

$\}$

$//$ Derived class for course work students

class Student$\_$Course extends Student $\{$

$$ private String enrolmentType;

$$ private String unitID;

$$ private double overallMark;

$$ private String finalGrade;

$$ public Student$\_$Course$($String firstName, String lastName, long studentID, String enrolmentType, String unitID, double overallMark, String finalGrade$)\{$

$$ super$($firstName$,$ lastName, studentID$)$;

$$ this.enrolmentType $=$ enrolmentType;

$$ this.unitID $=$ unitID;

$$ this.overallMark $=$ overallMark;

$$ this.finalGrade $=$ finalGrade;

$\}$

$$ @Override

$$ public void reportGrade$()\{$

$$ System.out.println$("$C: $"+$ getFirstName$()+""+$ getLastName$()+",$ Student ID: $"+$ getStudentID$()+",$ Unit ID: $"+$ unitID $+",$ Overall Mark: $"+$ overallMark $+",$ Final Grade: $"+$ finalGrade$)$;

$\}$

$\}$

$//$ Derived class for research students

class Student$\_$Research extends Student $\{$

$$ private String enrolmentType;

$$ private double overallMark;

$$ private String finalGrade;

$$ public Student$\_$Research$($String firstName, String lastName, long studentID, String enrolmentType, double overallMark, String finalGrade$)\{$

$$ super$($firstName$,$ lastName, studentID$)$;

$$ this.enrolmentType $=$ enrolmentType;

$$ this.overallMark $=$ overallMark;

$$ this.finalGrade $=$ finalGrade;

$\}$

$$ @Override

$$ public void reportGrade$()\{$

$$ System.out.println$("$R: $"+$ getFirstName$()+""+$ getLastName$()+",$ Student ID: $"+$ getStudentID$()+",$ Overall Mark: $"+$ overallMark $+",$ Final Grade: $"+$ finalGrade$)$;

$\}$

$\}$

$//$ Main class to test the implementation

public class Main $\{$

$$ public static void main$($String$[]$ args$)\{$

$$ ArrayList students $=$ new ArrayList$<>()$;

$//$ Create course work student

$$ Student$\_$Course courseStudent $=$ new Student$\_$Course$("$John$",$ "Doe", $123456,$ "Full$-$time", $"$CS$101",85\mathrm{.}5,"$A$")$;

$$ students.add$($courseStudent$)$;

$//$ Create research student

$$ Student$\_$Research researchStudent $=$ new Student$\_$Research$("$Jane$",$ "Smith", $654321,$ "Part$-$time", $90\mathrm{.}0,"$A$+")$;

$$ students.add$($researchStudent$)$;

$//$ Display information and report grades for all students

$$ for $($Student student : students$)\{$

$$ student.displayStudentInfo$()$;

$$ student.reportGrade$()$;

$$ System.out.println$()$;

$\}$

$\}$

$\}$