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Java performing code only from constructor's subclass

Is it possible to protect from performing code placed in superclass constructor? In this example the output is
From Person
From Student
but I don't need to print out From Person. If I delete super(a, n); then program will not compile. Is it possible to print out only message from subclass?
class Person {
private int age;
private String name;
public Person(int a, String n) {
this.age = a;
this.name = n;
System.out.println("From Person");
}
public int getAge() {
return age;
}
public void setAge(int a) {
this.age = a;
}
public String getName() {
return name;
}
public void setName(String n) {
this.name = n;
}
}
class Student extends Person {
private String specialization;
public Student(int a, String n, String s) {
super(a, n);
specialization = s;
System.out.println("From Student");
}
public String getSpecialization() {
return specialization;
}
public void setSpecialization(String s) {
this.specialization = s;
}
}
public class Classes {
public static void main(String[] args) {
Student student_Jack = new Student(20, "Jack", "IT");
}
}

Instead of using super(a,n) you should use your methods for setting those variables that you have made.
public Student(int a, String n, String s) {
setAge(a);
setName(n);
specialization = s;
System.out.println("From Student");
}
You must also add an empty constructor in person.
public Person(){}
This will give you the same functionality, without needing to call the super constructor.

toString() method is not inherting from its super class

I'm working on a task which has the following classes:
Vehicle.java ( Abstract Class)
NewVehicle.java subClass of Vehicle.java
UsedVehicle.java subClass of Vehicle.java
VehicleParser.java used as a parser
Drive Class which is used as main
In the VehicleParser class I determine which object it is. Either it is a NewVehicle object or a UsedVehicle. And in the Drive class I fill an ArrayList with the Vehicle objects.
Now When I'm trying to System.out.println an Arraylist the drive class is just invoking toString method declared in UsedVehicle/NewVehicle but not invoking the method declared in the Vehicle.java class. I need it to first invoke the method toString of Vehicle and then concat the toString of UsedVehicle/NewVehicle with it.
Here is the Code:
Vehicle
public abstract class Vehicle {
protected String make;
protected int modelYear;
protected String motivePower;
protected double licenseFee;
public Vehicle(String make,int modeYear,String motivePower) {
this.make = make;
this.modelYear= modeYear;
this.motivePower = motivePower;
this.licenseFee = 0.0;
}
public String getMake() {
return make;
}
public void setMake(String make) {
this.make = make;
}
public int getModelYear() {
return modelYear;
}
public void setModelYear(int modelYear) {
this.modelYear = modelYear;
}
public String getMotivePower() {
return motivePower;
}
public void setMotivePower(String motivePower) {
this.motivePower = motivePower;
}
public double getLicenseFee() {
return licenseFee;
}
public void setLicenseFee(double licenseFee) {
this.licenseFee = licenseFee;
}
public abstract void computeLicenseFee();
public String toString()
{
return "\nMake:\t\t"+getMake()+
"\nModel Year:\t"+getModelYear()+
"\n Motive Power:\t"+getMotivePower()+
"\nLicense Fee:\t"+getLicenseFee();
}
public static class UsedVehicle extends Vehicle
{
public String previousLicenseState;
public int currentYear;
int yearsOld = 0;
public UsedVehicle(String make, int modelYear, String power, String previousState, int currentYear)
{
super(make,modelYear,power);
this.previousLicenseState = previousState;
this.currentYear = currentYear;
}
public String getPreviousLicenseState() {
return previousLicenseState;
}
public void setPreviousLicenseState(String previousLicenseState) {
this.previousLicenseState = previousLicenseState;
}
public int getCurrentYear() {
return currentYear;
}
public void setCurrentYear(int currentYear) {
this.currentYear = currentYear;
}
public void computeLicenseFee() {
double baseFee = 100.00;
double titleTransferFee = 15.00;
double smogWaiverFee = 0.00;
double smogAbatement = 0.00;
yearsOld = getCurrentYear() - getModelYear();
if(yearsOld > 5)
{
smogWaiverFee = 8.00;
}
if("gas".equalsIgnoreCase(getMotivePower()))
{
smogAbatement = 20.00;
}
licenseFee = baseFee + smogAbatement + titleTransferFee + smogWaiverFee;
}
public String toString()
{
return "\n Years Old:\t"+yearsOld+
"\n Previous State:\t"+getPreviousLicenseState();
}
}
public static class NewVehicle extends Vehicle
{
public double vehiclePrice;
public NewVehicle(String make, int modeYear, String motivePower,double price) {
super(make, modeYear, motivePower);
this.vehiclePrice = price;
}
public double getVehiclePrice() {
return vehiclePrice;
}
public void setVehiclePrice(double vehiclePrice) {
this.vehiclePrice = vehiclePrice;
}
public void computeLicenseFee() {
double baseFee = 150.00;
double smogAbatement = 0.00;
double priceFee = 0.00;
if("gas".equalsIgnoreCase(getMotivePower()))
{
smogAbatement = 20.0;
priceFee = getVehiclePrice()*0.15;
}
licenseFee = baseFee + smogAbatement + priceFee;
}
public String toString()
{
return "Price:\t\t$"+getVehiclePrice();
}
}
}
Parser
public class VehicleParser {
public static Vehicle parseStringToVehicle(String lineToParse)
{
Vehicle vehicleObj = null;
Vehicle.UsedVehicle usedVeh = new Vehicle.UsedVehicle(make, modelYear, power, previousState, currentYear);
return vehicleObj;
}
}
DriveClass
Vehicle obj = VehicleParser.parseStringToVehicle(inputInfo);
vehicleList.add(obj);
System.out.println(vehicleList.get(i));

You are overriding the toString() method. Java doesn't do any special magic here. If you want the super class' method to be called, you need to do so explicitly with the super keyword:
#Override
public String toString()
{
return super.toString() + // Here
"\n Years Old:\t"+yearsOld+
"\n Previous State:\t"+getPreviousLicenseState();
}

Just consider this example:
public class A {
public String someMethod() {
return "A method";
}
}
public class B extends A {
#Override
public String someMethod() {
return "B method";
}
}
public class C extends B {
#Override
public String someMethod() {
return "C method";
}
}
Basically what's going on here is that when you inherit the parent class, you're overriding everything that's in parent class's method and you're giving new definition to it. By Overriding parent class's method, you're saying that:
I'm giving a new fresh definition to this method. From now onward, for all of my objects and my child's object, this is only going to be the definition that would be considered and any of parent's method definition is void.
Now if you want the parent's method definition to be called before calling this method definition, then you'd have to specifically state that using super.methodName() in your code.
public class A {
public String someMethod() {
return "A method";
}
}
public class B extends A {
#Override
public String someMethod() {
return super.someMethod() + "B method";
}
}
public class C extends B {
#Override
public String someMethod() {
return super.someMethod() + "C method";
}
}

When you call the subclass methods the overridden methods will be called and all the definitions in the parent's method will be overridden and you will get only the overridden method definition. So inprder to use the parents' method definition as well you need to use the super() method in your child class method...
return super.toString() + " is a new car!";

interface,abstract and classes

I am trying to complete the Appendix attached Appendix. I just want to know if I am coding it correctly according to the Appendix and that I am using the correct approach. I am not sure if I did the correct thing under interest(). Where I called the super classes is that correct?
public interface LoanInterest {
double interest();
String getName();
String toString();
} //end of LoanInterest
public abstract class Student implements LoanInterest {
private String name;
private String studentNumber;
private double feesOwed;
public Student(String nm, String num, double amt) {
name = nm;
studentNumber = num;
feesOwed = amt;
}
public double getFeesOwed() {
return feesOwed;
}
public String getStudentNumber() {
return studentNumber;
}
public String getName() {
return name;
}
public String toString() {
String msg;
msg = String.format("%s\t%s\t%.2f", name, getStudentNumber(), getFeesOwed());
return msg;
}
} //end of Student
public class UnderGrad extends Student {
public UnderGrad(String nm, String num, double amt) {
super(nm, num, amt);
}
public double interest() {
return super.getFeesOwed() + (super.getFeesOwed() * 0.14);
}
} //end of UnderGrad
public class PostGrad extends Student {
private String diploma;
public PostGrad(String nm, String num, double amt) {
super(nm, num, amt);
}
public String getDiploma() {
return diploma;
}
public double interest() {
return super.getFeesOwed() + (super.getFeesOwed() * 0.14);
}
} //end of PostGrad

You don't need to call super.methodName, since you do not override them in PostGrad or UnderGrad, but it is not "wrong" either.
So you can write:
public double interest() {
return getFeesOwed() + (getFeesOwed() * 0.14);
}
And if you would override them, you most likely want to use them too, so again no super.
The super keyword is normally used, if a method is overridden to add some additional functionality to it, without completely rewriting the code of the overridden method.

How to add value from another class (java)

I have two classes: profesor and subject
public class Profesor {
private int numbClassroom;
public Profesor(int numbClassroom) {
this.numbClassroom = numbClassroom;
}
public int getNumbClassroom() {
return numbClassroom;
}
public void setNumbClassroom(int numbClassroom) {
this.numbClassroom = numbClassroom;
}
public String ToString(){
return "Number of classroom: "+numbClassroom;
} }
The second class is:
public class Subject{
String name;
Profesor lecturer = new Profesor();
Date yearOfStudy;
public void Dodeli(Profesor p){
??????
}}
I do not know how to add professor like a lecturer to a current subject

Like this? I don't see any problem.
public void Dodeli(Profesor p){
lecturer = p;
}

Profesor lecturer = new Profesor();
No need to instantiate lecturer. Just declare it. Then have getter/setter methods for it
Then you can assign Professor to Subject
Subject subj = new Subject("OOP"); //assuming you have corresponding constructor
subj.setLecturer(new Professor()); //or if you have existing prof object

Maybe require something like this : try to encapsulate your code
public class Professor {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public class Subject{
private String name;
private Professor professor;
private int numbClassroom;
private Date yearOfStudy;
public int getNumbClassroom() {
return numbClassroom;
}
public void setNumbClassroom(int numbClassroom) {
this.numbClassroom = numbClassroom;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Professor getProfesor() {
return professor;
}
public void setProfesor(Professor profesor) {
this.professor = profesor;
}
public void Dodeli(){
System.out.println("Pofessor "+getProfesor().getName()+" is teaching "+getName()+" in Room NO :"+getNumbClassroom());
}
}
public class TestImpl {
public static void main(String arr[])
{
Subject subject = new Subject();
Professor professor = new Professor();
subject.setName("Biology");
professor.setName("MR.X");
subject.setNumbClassroom(1111);
subject.setProfesor(professor);
subject.Dodeli();
}
}

Convert Object to String

I have a couple to class in which I'm getting and setting a few things and then finally calling it in my main method. But when I call my class in the main method it just gives me the object instead of name,address and age. I know this structure is very complicated but I want to keep this structure because later on I will be adding a lot of things to this. It would be AMAZING if someone could tell me how to do this. I would really appreciate this. Below is my code for all my classes
This is my first class
public class methodOne
{
public String getName()
{
String name = "UserOne";
return name;
}
public int getAge()
{
int age = 17;
return age;
}
public String getAddress()
{
String address = "United States";
return address;
}
}
This is my second class
public class methodTwo
{
String name;
String address;
int age;
public methodTwo(methodOne objectOne)
{
name=objectOne.getName();
address=objectOne.getAddress();
age=objectOne.getAge();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
This is my third class
public class methodThree {
private methodTwo methodTwoInMethodThree;
private methodOne methodOneInMethodThree;
public methodThree()
{
this.methodOneInMethodThree = new methodOne();
this.methodTwoInMethodThree = new methodTwo(methodOneInMethodThree);
}
public methodTwo getMethodTwoInMethodThree() {
return methodTwoInMethodThree;
}
public void setMethodTwoInMethodThree(methodTwo methodTwoInMethodThree) {
this.methodTwoInMethodThree = methodTwoInMethodThree;
}
}
This is my fourth class which is the method maker
public class methodMaker {
public methodThree brandNewFunction(methodTwo object)
{
methodThree thirdMethod = new methodThree();
thirdMethod.setMethodTwoInMethodThree(object);
return thirdMethod;
}
}
This is my main class which calls methodMaker. What I want to achieve is that when I print the value it should print the name,address and age but instead it just prints trial.methodThree#4de5ed7b
public class mainClass {
public static void main(String args[])
{
methodMaker makerOfMethods = new methodMaker();
methodOne one = new methodOne();
methodTwo object = new methodTwo(one);
System.out.println(makerOfMethods.brandNewFunction(object).toString());
}
}

What you need to do is to override the default implementation of the .toString() method in the objects you want to print out:
#Override
public String toString()
{
return "Name: " + this.name;
}
EDIT:
I do not know exactly where you are printing, and you naming convention doesn't really help out, but from what I am understanding, you would need to implement it in all of you classes since they all seem to be related to each other.
So, in your methodOne class (can also be applied to methodTwo):
#Override
public String toString()
{
return "Name: " + this.name + " Age: " + this.age + " Address: + " this.address;
}
In your methodThree class:
private methodTwo methodTwoInMethodThree;
private methodOne methodOneInMethodThree;
#Override
public String toString()
{
StringBulder sb = new StringBuilder();
if(this.methodTwoInMethodThree != null)
{
sb.append("Method 2:").append(methodTwoInMethodThree.toString());
}
if(methodOneInMethodThree != null)
{
sb.append("Method 1:").append(methodOneInMethodThree.toString());
}
return sb.toString();
}

When you call
MyClass myObject = new MyClass();
System.out.println(myObject);
Implicitly , java calls instead
System.out.println(myObject.toString());
So, if in MyClass, you override toString(), then whatever your toString method returns is what's gonna be printed.
Side note: are you confusing classes and methods? Methods are functions in your classes, classes are wrappers around a bunch of attributes and methods. Your naming is confusing.

try this code:
public class methodTwo
{
String name;
String address;
int age;
public methodTwo(methodOne objectOne)
{
name=objectOne.getName();
address=objectOne.getAddress();
age=objectOne.getAge();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String toString(){
return name+" "+address+" "+age;
}
}

Are you printing the object using println()?
From the docs, println():
calls at first String.valueOf(x) to get the printed object's string value
This string value is obtained from the object's toString() method, which:
returns a string consisting of the name of the class of which the object is an instance, the at-sign character `#', and the unsigned hexadecimal representation of the hash code of the object
So if you want to print anything other than this you have to override the toString() method in your object and return a string containing whatever you want.
Just google "override tostring java" and you will see a ton of examples.