Class is not abstract and does not override abstract method compareTo(X) in Comparable

I’m trying to use the comparable interface to compare the appointment times (String) in the format of dd-mm-yyyy hh:mm
Also it seems that it can’t find the getAppointmentTime method, which is clearly there

In the tester class, I’m guessing I should just use Collection.sort and that’s it.

But these are the errors I’m getting…

HW3\Appointment.java:13: error: Appointment is not abstract and does not override abstract method compareTo(Appointment) in Comparable
public class Appointment implements Comparable<Appointment>
       ^
HW3\Appointment.java:189: error: name clash: compareTo(Object) in Appointment and compareTo(Appointment) in Comparable have the same erasure, yet neither overrides the other
    public int compareTo(Object obj)
               ^
HW3\Appointment.java:191: error: cannot find symbol
        return getAppointmentTime().compareTo(obj.getAppointmentTime());
                                                 ^
  symbol:   method getAppointmentTime()
  location: variable obj of type Object

Code:

package HW3;

import java.lang.Comparable;

public class Appointment implements Comparable<Appointment>
{

private String serviceType;
private int patientID;
private String patientName;
private String appointmentTime;
private String doctorName;
private String symptoms;

public Appointment(String serviceType, int patientID, String patientName, String appointmentTime, String doctorName, String symptoms)
{
this.serviceType = serviceType;
this.patientID = patientID;
this.patientName = patientName;
this.appointmentTime = appointmentTime;
this.doctorName = doctorName;
this.symptoms = symptoms;
}

public String getServiceType()
{
  return serviceType;
}


public int getPatientID()
{
  return patientID;
}


public String getPatientName()
{
  return patientName;
}


public String getAppointmentTime()
{
  return appointmentTime;
}


public String getDoctorName()
{
  return doctorName;
}

public String getSymptoms()
{
  return symptoms;
}

public int compareTo(Object obj)
{
    return getAppointmentTime().compareTo(obj.getAppointmentTime());
}

}

>Solution :

Try the below code:

package HW3;

import java.lang.Comparable;

public class Appointment implements Comparable<Appointment> {

private String serviceType;
private int patientID;
private String patientName;
private String appointmentTime;
private String doctorName;
private String symptoms;

public Appointment(String serviceType, int patientID, String patientName, String appointmentTime, String doctorName, String symptoms) {
    this.serviceType = serviceType;
    this.patientID = patientID;
    this.patientName = patientName;
    this.appointmentTime = appointmentTime;
    this.doctorName = doctorName;
    this.symptoms = symptoms;
}

public String getServiceType() {
    return serviceType;
}


public int getPatientID() {
    return patientID;
}


public String getPatientName() {
    return patientName;
}


public String getAppointmentTime() {
    return appointmentTime;
}


public String getDoctorName() {
    return doctorName;
}

public String getSymptoms() {
    return symptoms;
}

@Override
public int compareTo(Appointment obj) {
    return getAppointmentTime().compareTo(obj.getAppointmentTime());
 }
}

Changes:
Changed the method parameter of compareTo method from Object to Appointment