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How to get rid of syntax error on token "public" in main class?

I am getting a syntax error in my main class when I call the constructor from another class that I need for the main program to run. This program is focused on inheritance and the appropriate calling of constructors and arguments. This is the error message I get during compilation:
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Syntax error on token "public", record expected after this token
at a6main.main(a6main.java:7)
This is the line of code that is causing the error:
PreferredCustomer c = new PreferredCustomer("Al", "222BurdSt", "2102223321", "46821",
"2000", true, "1000");
The rest of the code can be found below:
class person {
String Name;
String Address;
String Telephone;
person (String Name, String Address, String Telephone) {
this.Name = Name;
this.Address = Address;
this.Telephone = Telephone;
}
String getName() {
return Name;
}
String getAddress() {
return Address;
}
String getTelephone() {
return Telephone;
}
void setName(String Name) {
this.Name = Name;
}
void setAddress(String Address) {
this.Address = Address;
}
void setTelephone(String Telephone) {
this.Telephone = Telephone;
}
}
public class customer extends person {
String number;
boolean OnMailingList;
//constructor and getters and setters
customer (String Name, String Address, String Telephone, String number, boolean OnMailingList) {
//inherit persons information
super(Name, Address, Telephone);
this.number = number;
this.OnMailingList = OnMailingList;
}
String getnumber() {
return number;
}
void setnumber(String number) {
this.number = number;
}
boolean OnMailingList () {
return OnMailingList;
}
void setOnMailingList(boolean OnMailingList) {
this.OnMailingList = OnMailingList;
}
}
public class PreferredCustomer extends customer {
private int purchase;
double discount;
/**public constructor so its accessible to main
* else ifs for certain percentage of discounts
* getters and setters for purchase and discount
* super to inherit other features from other classes */
public int getpurchase() {
return purchase;
}
public double getdiscount () {
return this.discount;
}
public void setPurchase(int purchase) {
this.purchase = purchase;
}
public PreferredCustomer(String Name, String Address, String Telephone, String number, int pur,
boolean OnMailingList, double Discount, PreferredCustomer preferredCustomer) {
super(Name, Address, Telephone, number, OnMailingList);
this.purchase = pur;
preferredCustomer.discount = discount;
if (this.purchase>= 2000) {
this.discount = 10;
} else if (this.purchase>= 1500) {
this.discount = 7;
} else if (this.purchase>= 1000) {
this.discount = 6;
} else if (this.purchase >= 500) {
this.discount = 5;
}
}
}
public class a6main {
public static void main (String [] args) {
public PreferredCustomer() {
}
PreferredCustomer c = new PreferredCustomer("Al", "222BurdSt", "2102223321", "46821","2000", true, "1000");
System.out.println("Name: " + c.getName());
System.out.println("Address: " + c.getAddress());
System.out.println("Telephone number: " + c.getTelephone());
System.out.println("Customer ID: " + c.getnumber());
System.out.println("Amount spent: " + c.getpurchase());
System.out.println("On mailing list: " + c.OnMailingList());
System.out.println("Discount: " + c.getdiscount());
}
}

You have several mistakes here. I've corrected them, and the program launches, providing the result:
Name: Al
Address: 222BurdSt
Telephone number: 2102223321
Customer ID: 46821
Amount spent: 2000
On mailing list: true
Discount: 10.0
Remove PreferredCustomer constructor from the main method. It can't be a part of a
method, it is a part of a class. Then, the constructor for PreferredCustomer is already present in PreferredCustomer class.
Hopefully, your customer and PreferredCustomer classes are in separate files? If not, put them in separate files named customer.java and PreferredCustomer.java. In PreferredCustomer class constructor, remove PreferredCustomer preferredCustomer from arguments. It's redundant: why you need to pass one customer into another? Do customers have any relationships with each other? Now the number of arguments will match when you call the constructor (and don't use strings "2000", "1000" where should be integers):
PreferredCustomer c = new PreferredCustomer("Al", "222BurdSt", "2102223321", "46821",
2000, true, 1000);
Further in the PreferredCustomer constructor, use this instead of preferredCustomer here: this.discount = Discount; and print Discount with upper case, as in the signature of the constructor.
As a result, the code of the constructor should be:
public PreferredCustomer(String Name, String Address, String Telephone, String number, int pur, boolean OnMailingList, double Discount) {
super(Name, Address, Telephone, number, OnMailingList);
this.purchase = pur;
this.discount = Discount;
if (this.purchase>= 2000) {
this.discount = 10;
} else if (this.purchase>= 1500) {
this.discount = 7;
} else if (this.purchase>= 1000) {
this.discount = 6;
} else if (this.purchase >= 500) {
this.discount = 5;
}
}
The main method in a6main class:
public static void main (String [] args) {
PreferredCustomer c = new PreferredCustomer("Al", "222BurdSt", "2102223321", "46821", 2000, true, 1000);
System.out.println("Name: " + c.getName());
System.out.println("Address: " + c.getAddress());
System.out.println("Telephone number: " + c.getTelephone());
System.out.println("Customer ID: " + c.getnumber());
System.out.println("Amount spent: " + c.getpurchase());
System.out.println("On mailing list: " + c.OnMailingList());
System.out.println("Discount: " + c.getdiscount());
}
And take care of naming conventions, as other people pointed.

File with multiple data types, into arrays, then sort one array while keeping the records together

My problem is that I will be giving a file with student information: name, age, and GPA. I then have to turn each data element into a separate array. I then have to sort GPA into descending order, while keeping name and age with the corresponding GPA, and then print it out with "Name Age GPA" heading.

Check below code to sort data based on GPA. However you will have to include relevant code for file reading.
Student.java (POJO)
public class Student {
String name;
int age;
double GPA;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getGPA() {
return GPA;
}
public void setGPA(double gPA) {
GPA = gPA;
}
public Student(String name, int age, double gPA) {
super();
this.name = name;
this.age = age;
GPA = gPA;
}
#Override
public String toString() {
return "Student [name=" + name + ", age=" + age + ", GPA=" + GPA + "]";
}
}
StudentSorter.java
import java.util.Comparator;
public class StudentSorter implements Comparator<Student> {
#Override
public int compare(Student o1, Student o2) {
if(o1.getGPA() < o2.getGPA()) return 1;
if(o1.getGPA() > o2.getGPA()) return -1;
else return 0;
}
}
Tester.java
public class Tester {
public static void main(String[] args) {
Student s1 = new Student("A",14,7.9);
Student s2 = new Student("B",17,8.2);
Student s3 = new Student("C",20,7.0);
Student s4 = new Student("D",15,6.9);
Student s5 = new Student("E",14,9.1);
List<Student> list = new ArrayList<>();
list.add(s1);
list.add(s2);
list.add(s3);
list.add(s4);
list.add(s5);
StudentSorter ss = new StudentSorter();
Collections.sort(list, ss);
System.out.println(list.toString());
}
}

Creating two constructors with objects that call to other java files

I don't really know if my question makes sense but my assignment says:
"Write a third class, StudentRecord, that has two attributes:
Student stu;
Address addr;
and two constructors. The first constructor is given a Student object and an Address object to initialize the attributes. The second constructor is given a first name, a last name, a student ID, a gpa, a street address, a city, a state, and a zipcode and uses these to initialize the attributes"
I don't understand how exactly I'm supposed to make two constructors take info from two different java files.
Here's the code I have for the third class named "StudentRecord".
I have no doubt it's incorrect.
public class StudentRecord {
Student stu;
Address addr;
public StudentRecord() {
Student stu;
Address addr;
}
public StudentRecord(String _fName, String _lName, int _id, double _gpa, String _street, String _city, String _state, int _zip){
}
public String toString() {
return String.format(stu + "\n" + addr);
}
}
Here's the code I have for the TestStudentRecord class, all I get is
"null null" when I run the program.
public class TestStudentRecord {
public static void main(String[] args) {
StudentRecord stu1 = new StudentRecord("Jane", "Brown", 182765, 2.333, "13 Flower St.", "Pulteneyville", "NY", 14386);
System.out.println(stu1);
}
}
All I get is "null null" when I run the program instead of the toString method giving me the student info I have typed into the test class.
For those asking for the Student and Address classes, here you go:
public class Student {
// attributes of a Student
private String firstName;
private String lastName;
private int studentId;
private double gpa;
/**
* Student constructor.
* #param _fName student's first name
* #param _lName student's last name
* #param _id student's id number
* #param _gpa students GPA
*/
public Student(String _fName, String _lName, int _id, double _gpa) {
firstName = _fName;
lastName = _lName;
studentId = _id;
gpa = _gpa;
}
/**
* getFirstName - Accessor for first name
* #return the student's first name
*/
public String getFirstName() {
return firstName;
}
/**
* getLastName - Accessor for last name
* #return the student's last name
*/
public String getLastName() {
return lastName;
}
/**
* getId - Accessor for ID
* #return the student's ID
*/
public int getStudentId() {
return studentId;
}
/**
* getGpa - Accessor for gpa
* #return the student's gpa
*/
public double getGpa() {
return gpa;
}
/**
* setFirstName - Mutator for first name
* #param the new first name
*/
public void setFirstName(String _fName) {
firstName = _fName;
}
/**
* setLastName - Mutator for last name
* #param the new last name
*/
public void setLastName(String _lastName) {
lastName = _lastName;
}
/**
* setStudentId - Mutator for ID
* #param the new ID
*/
public void setStudentId(int _id) {
studentId = _id;
}
/**
* setGpa - Mutator for gpa
* #param the new gpa
*/
public void setGpa(double _gpa) {
gpa = _gpa;
}
// toString Method
public String toString() {
return String.format(getLastName() + ", " + getFirstName() + "\n" + "ID: " + getStudentId() + " GPA: %3.1f", getGpa());
}
}
public class Address {
private String street;
private String city;
private String state;
private int zip;
public Address(String _street, String _city, String _state, int _zip) {
street = _street;
city = _city;
state = _state;
zip = _zip;
}
// Accessors
public String getStreet() {
return street;
}
public String getCity() {
return city;
}
public String getState() {
return state;
}
public int getZip() {
return zip;
}
// Mutators
public void setStreet(String _street) {
street = _street;
}
public void setCity(String _city) {
city = _city;
}
public void setState(String _state) {
state = _state;
}
public void setZip(int _zip) {
zip = _zip;
}
// toString Method
public String toString() {
return String.format(getStreet() + "\n" + getCity() + ", " + getState() + " " + getZip());
}
}

would suggest you to please follow below approach to initialize your object through argumented construtor.
public class StudentRecord {
Student stu;
Address addr;
public StudentRecord() {
Student stu;
Address addr;
}
public StudentRecord(String _fName, String _lName, int _id, double _gpa, String _street, String _city, String _state, int _zip){
this.stu = new Student(_fName, _lName, _id, _gpa);
this.addr=new Address(_street,_city,_state,_zip);
}
public String toString() {
return String.format(stu + "\n" + addr);
}
}
As you have already overided toString method in address and student class so you will get the object.

Your constructor is like below. Empty Constructor will not assign values to your class variables.
public StudentRecord(String _fName, String _lName, int _id, double _gpa, String _street, String _city, String _state, int _zip){
}
it should be like below as mentioned by Eran.
public StudentRecord(String _fName, String _lName, int _id, double _gpa, String _street, String _city, String _state, int _zip){
this.stu = new Student(_fName, _lName, _id, _gp);
this.addr = new Address(_street, _city, _state, _zip);
}
Now your toString will have the values for stu and addr. Which will get printed.

You have to initilize the variables with this.{variable name} = {variable name}.
Also it is often better to chain the Constructors (see How do I call one constructor from another in Java?), in this way changes in classes, with many constructors, are way easier to implement.
I would also suggsest to rename your variables, because in Java they should not start with an underscore (see https://www.javatpoint.com/java-naming-conventions).
public class StudentRecord {
Student student;
Address addr;
public StudentRecord(Student student, Address addr) {
this.student = student;
this.addr = addr;
}
public StudentRecord(String fName, String lName, int id, double gpa, String street, String city, String state, int zip){
this(new Student(fName, lName, id, gpa),
new Address(street,city,state,zip));
}
public String toString() {
return String.format(student + "\n" + addr);
}
}

How to add multiple students to student class?

Im trying to create a student class, a course class and the main class. I am trying to add students to the course, and when students are added to the class the number of students in the course should increase, when the the code is run it should print the course details followed by the students in the course.
I have got the following code:
Main class:
public class JavaLecture3 {
public static final int DEBUG = 0;
public static void main(String [] args){
//Student student = new Student(); // Calling default constructor here.
Course course = new Course();
student = new Student(21, "Joe", "CSE", "07447832342");
course = new Course("CSE", "Tom", 5);
System.out.println("Course Information: ");
System.out.println("-------------------");
System.out.println(course);
System.out.println();
System.out.println("Student contains: "); // calls student.toString());
System.out.println("-------------------");
System.out.println(student);
}
}
Course class:
public class Course {
ArrayList<Student> studentList;
private String courseName;
private String teacher;
private int noOfStudents;
//Getters
public String getCourseName(){
return this.courseName;
}
public int getNoOfStudents(){
return this.noOfStudents;
}
public String getTeacher(){
return this.teacher;
}
//Setters
public void setCourseName(String courseName){
this.courseName = courseName;
}
public void setNoOfStudents(int noOfStudents){
this.noOfStudents = noOfStudents;
}
public void setTeacher(String teacher){
this.teacher = teacher;
}
/**
* Default constructor. Populates course name, number of students with defaults
*
*/
public Course(){
this.noOfStudents = 0;
this.courseName = "Not Set";
this.teacher = "Not Set";
studentList = new ArrayList<Student>();
}
/**
* Constructor with parameters
* #param noOfStudents integer
* #param courseName String with the Course name
* #param teacher String with the teacher
*/
public Course(String courseName, String teacher, int noOfStudents){
this.courseName = courseName;
this.teacher = teacher;
noOfStudents = noOfStudents;
studentList = new ArrayList<Student>();
}
public static void addStudent(Student newStudent){
if(studentList.size()==noOfStudents){
System.out.println("The class is full, you cannot enrol.");
}
else {
studentList.add(newStudent);
}
}
public String toString() {
return "Course Name: " + this.courseName + " Teacher: " + this.teacher
+ " Number of Students: " + this.noOfStudents;
}
}
Student class:
public class Student {
private String name;
private int age;
public String gender = "na";
private String course;
private String phoneNo;
public static int instances = 0;
// Getters
public int getAge(){
return this.age;
}
public String getName(){
return this.name;
}
public String getCourse(){
return this.course;
}
public String getPhoneNo(){
return this.phoneNo;
}
// Setters
public void setAge(int age){
this.age = age;
}
public void setName(String name){
if (JavaLecture3.DEBUG > 3) System.out.println("In Student.setName. Name = "+ name);
this.name = name;
}
public void setCourse(String course){
this.course = course;
}
public void setPhoneNo(String phoneNo){
this.phoneNo = phoneNo;
}
/**
* Default constructor. Populates name,age,gender,course and phone Number
* with defaults
*/
public Student(){
instances++;
this.age = 18;
this.name = "Not Set";
this.gender = "Not Set";
this.course = "Not Set";
this.phoneNo = "Not Set";
}
/**
* Constructor with parameters
* #param age integer
* #param name String with the name
* #param course String with course name
* #param phoneNo String with phone number
*/
public Student(int age, String name, String course, String phoneNo){
this.age = age;
this.name = name;
this.course = course;
this.phoneNo = phoneNo;
}
/**
* Gender constructor
* #param gender
*/
public Student(String gender){
this(); // Must be the first line!
this.gender = gender;
}
protected void finalize() throws Throwable{
//do finalization here
instances--;
super.finalize(); //not necessary if extending Object.
}
public String toString (){
return "Name: " + this.name + " Age: " + this.age + " Gender: "
+ this.gender + " Course: " + this.course + " Phone number: "
+ this.phoneNo;
}
}

Reference:
http://docs.oracle.com/javase/7/docs/api/java/util/ArrayList.html?is-external=true
Course.getNoOfStudents should just return studentList.size(). No need to maintain a separate variable.
To print a list of students (from Course):
for(int i=0;i<studentList.size();i++) System.out.println(studentList.get(i));

Since you initialized the array list in the Course class, you should add the students to it. You should create a method in Course that adds an object to the array list such as:
public void addStudent(Student s){
studentList.add(s);
noOfStudents++;
}
To add multiple students:
public void addStudents(Student[] students){
for(int i = 0; i < students.length; i++){
studentList.add(students[i]);
}
}
You're almost there, just use the .add method made for you in the array list.

public class JavaLecture3 {
public static final int DEBUG = 0;
public static void main(String [] args){
Student student = new Student(); // Calling default constructor here.
Course course = new Course();
student = new Student(21, "Joe", "CSE", "07447832342");
course = new Course("CSE", "Tom", 5);
course.addStudent(student);
System.out.println("Course Information: ");
System.out.println("-------------------");
System.out.println(course);
System.out.println();
System.out.println("Student contains: "); // calls student.toString());
System.out.println("-------------------");
System.out.println(student);
}
}
public class Course {
List<Student> studentList;
private String courseName;
private String teacher;
private int noOfStudents;
// Getters
public String getCourseName() {
return this.courseName;
}
public int getNoOfStudents() {
return this.noOfStudents;
}
public String getTeacher() {
return this.teacher;
}
// Setters
public void setCourseName(String courseName) {
this.courseName = courseName;
}
public void setNoOfStudents(int noOfStudents) {
this.noOfStudents = noOfStudents;
}
public void setTeacher(String teacher) {
this.teacher = teacher;
}
/**
* Default constructor. Populates course name, number of students with
* defaults
*
*/
public Course() {
this.noOfStudents = 0;
this.courseName = "Not Set";
this.teacher = "Not Set";
studentList = new ArrayList<Student>();
}
/**
* Constructor with parameters
*
* #param noOfStudents
* integer
* #param courseName
* String with the Course name
* #param teacher
* String with the teacher
*/
public Course(String courseName, String teacher, int noOfStudents) {
this.courseName = courseName;
this.teacher = teacher;
this.noOfStudents = noOfStudents;
studentList = new ArrayList<Student>();
}
public void addStudent(Student newStudent) {
if (studentList.size() == noOfStudents) {
System.out.println("The class is full, you cannot enrol.");
} else {
studentList.add(newStudent);
}
}
#Override
public String toString() {
return "Course Name: " + this.courseName + " Teacher: " + this.teacher
+ " Number of Students: " + studentList.size();
}
}
public class Student {
private String name;
private int age;
public String gender = "na";
private String course;
private String phoneNo;
public static int instances = 0;
// Getters
public int getAge() {
return this.age;
}
public String getName() {
return this.name;
}
public String getCourse() {
return this.course;
}
public String getPhoneNo() {
return this.phoneNo;
}
// Setters
public void setAge(int age) {
this.age = age;
}
public void setName(String name) {
if (JavaLecture3.DEBUG > 3)
System.out.println("In Student.setName. Name = " + name);
this.name = name;
}
public void setCourse(String course) {
this.course = course;
}
public void setPhoneNo(String phoneNo) {
this.phoneNo = phoneNo;
}
/**
* Default constructor. Populates name,age,gender,course and phone Number
* with defaults
*/
public Student() {
instances++;
this.age = 18;
this.name = "Not Set";
this.gender = "Not Set";
this.course = "Not Set";
this.phoneNo = "Not Set";
}
/**
* Constructor with parameters
*
* #param age
* integer
* #param name
* String with the name
* #param course
* String with course name
* #param phoneNo
* String with phone number
*/
public Student(int age, String name, String course, String phoneNo) {
this.age = age;
this.name = name;
this.course = course;
this.phoneNo = phoneNo;
}
/**
* Gender constructor
*
* #param gender
*/
public Student(String gender) {
this(); // Must be the first line!
this.gender = gender;
}
protected void finalize() throws Throwable {
// do finalization here
instances--;
super.finalize(); // not necessary if extending Object.
}
public String toString() {
return "Name: " + this.name + " Age: " + this.age + " Gender: "
+ this.gender + " Course: " + this.course + " Phone number: "
+ this.phoneNo;
}
}

public class JavaLecture3 {
public static final int DEBUG = 0;
public static void main(String [] args){
//Create course object
Course course = new Course("CSE", "Tom", 5);
Scanner scanner = new Scanner(System.in);
String cmd = "Yes";
while(cmd.equals("Yes")){
Student student = new Student();
System.out.print("Enter a new student? ");
cmd = scanner.next();
if (cmd.equals("Yes")){
//Read student name
System.out.print("Enter a student name: ");
String name = scanner.next();
student.setName(name);
//Read student Age
System.out.print("Enter a student age: ");
int age = scanner.nextInt();
student.setAge(age);
//Read student Course
System.out.print("Enter a student course: ");
String stdent_course = scanner.next();
student.setCourse(stdent_course);
//register the student to the class
course.addStudent(student);
}
}
scanner.close();
System.out.println("Course Information: ");
System.out.println("-------------------");
System.out.println(course.toString());
System.out.println();
}
}
I reworked a bit your toString() method from Course class. This should print the list of students attending a class.
public String toString (){
String ret_value = "Name: " + this.name + " Age: " + this.age + " Gender: "
+ this.gender + " Course: " + this.course + " Phone number: "
+ this.phoneNo + " Students attending this course:";
for (Student student: studentList) {
ret_value = ret_value + " " + Student.getName();
}
return ret_value;
}

ERROR actual and formal argument lists differ in length

constructor Student in class javaapplication 14.Student cannot be
applied to given types; required:
java.lang.String,int,java.lang.String,java.lang.String,double found:
java.lang.String,double reason: actual and formal argument lists
differ in length
This is the line that gives me error
super(idNum, gpa);
here is my code:
package javaapplication14;
public class JavaApplication14
{
public static void main(String[] args)
{
Person bob = new Person("Coach Bob", 27, "M");
System.out.println(bob);
Student lynne = new Student("Lynne Brooke", 16, "F", "HS95129", 3.5);
System.out.println(lynne);
Teacher mrJava = new Teacher("Duke Java",34,"M","Computer Science",50000);
System.out.println(mrJava);
}
}
class Person
{
protected String myName ;
protected int myAge;
protected String myGender;
public Person(String name, int age, String gender)
{
myName = name;
myAge = age ;
myGender = gender;
}
#Override
public String toString()
{
return myName + ", age: " + myAge + ", gender: " +myGender;
}
//These are the set methods
void setName(String name)
{
myName = name;
}
void setAge(int age)
{
myAge = age ;
}
void setGender(String gender)
{
myGender = gender;
}
//These are the get methods
String myName()
{
return myName;
}
int myAge()
{
return myAge;
}
String myGender()
{
return myGender;
}
}
class Student extends Person
{
protected String myIdNum;
protected double myGPA;
public Student(String name, int age, String gender,String idNum, double gpa)
{
super(name, age, gender);
myIdNum = idNum;
myGPA = gpa;
}
//These are the set methods
void setmyIdNum(String idNum)
{
myIdNum = idNum;
}
void setmyGPA(double gpa)
{
myGPA = gpa;
}
#Override
public String toString()
{
return super.toString() + ", student id: " + myIdNum + ", gpa: " + myGPA;
}
public String myIdNum()
{
return myIdNum;
}
double myGPA()
{
return myGPA;
}
}
class Teacher extends Person
{
public double mySalary;
public String mysubjectName;
public Teacher( String name, int age, String gender, String
subjectName,double salary )
{
super(name, age, gender);
mysubjectName = subjectName;
mySalary = salary;
}
//These are the setter methods
void setsubjectname(String subjectName)
{
mysubjectName = subjectName;
}
void setsalary(double Salary)
{
mySalary = Salary;
}
#Override
public String toString()
{
return super.toString() + ", subject name: " + mysubjectName + ", Salary: "
+ mySalary;
}
//These are the getter methods
public String getsubjectname(String subjectName)
{
return subjectName;
}
double getsalary(double Salary)
{
return Salary ;
}
class CollegeStudent extends Student
{
public String myMajor;
public int myYear;
public CollegeStudent(String name, int age,String gender,
String idNum, double gpa, int year, String major )
{
super(idNum, gpa);
myMajor = major;
myYear = year;
}
void setmajor(String Major)
{
myMajor = Major;
}
void setyear(int Year)
{
myYear = Year;
}
#Override
public String toString()
{
return super.toString() + ", major: " + myMajor + ", Year: " + myYear;
}
//These are the getter methods
public String getmajor(String myMajor)
{
return myMajor;
}
public int getyear(int myYear)
{
return myYear ;
}
}
}

There is no such constructor with two parameters in Student class

The class Student and also the class Person has no constuctor with the signature (String, double).
So you have to create this constructor in one of the superclasses or you have to call an other constructor.

Your super class Student has following constructor with 5 parameter
public Student(String name, int age, String gender,String idNum, double gpa)
But, at CollegeStudent constructor, super(idNum, gpa); expect a constructor with two parameter Student(String idNum, double gpa), which is missing in superclass. So, define a constructor at Student class like:
class Student extends Person {
public Student(String idNum, double gpa){
}
}