Not sure how to use getTime() with GregorianCalendar in Java

Question

I'm getting a long printout of my GregorianCalendar when I only want to print the Year, Month, and Day.

This is what I get:

dateOfBirth=java.util.GregorianCalendar[time=173592000000,areFieldsSet=true,areAllFieldsSet=false,lenient=true,zone=sun.util.calendar.ZoneInfo[id="America/New_York",offset=-18000000,dstSavings=3600000,useDaylight=true,transitions=235,lastRule=java.util.SimpleTimeZone[id=America/New_York,offset=-18000000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=8,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=3,endMonth=10,endDay=1,endDayOfWeek=1,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=?,YEAR=1975,MONTH=6,WEEK_OF_YEAR=?,WEEK_OF_MONTH=?,DAY_OF_MONTH=3,DAY_OF_YEAR=?,DAY_OF_WEEK=?,DAY_OF_WEEK_IN_MONTH=?,AM_PM=0,HOUR=0,HOUR_OF_DAY=0,MINUTE=0,SECOND=0,MILLISECOND=?,ZONE_OFFSET=?,DST_OFFSET=?]}Faculty{dateOfHire=java.util.GregorianCalendar[time=173592000000,areFieldsSet=true,areAllFieldsSet=false,lenient=true,zone=sun.util.calendar.ZoneInfo[id="America/New_York",offset=-18000000,dstSavings=3600000,useDaylight=true,transitions=235,lastRule=java.util.SimpleTimeZone[id=America/New_York,offset=-18000000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=8,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=3,endMonth=10,endDay=1,endDayOfWeek=1,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=?,YEAR=1975,MONTH=6,WEEK_OF_YEAR=?,WEEK_OF_MONTH=?,DAY_OF_MONTH=3,DAY_OF_YEAR=?,DAY_OF_WEEK=?,DAY_OF_WEEK_IN_MONTH=?,AM_PM=0,HOUR=0,HOUR_OF_DAY=0,MINUTE=0,SECOND=0,MILLISECOND=?,ZONE_OFFSET=?,DST_OFFSET=?], dateOfTermination=java.util.GregorianCalendar[time=173592000000,areFieldsSet=true,areAllFieldsSet=false,lenient=true,zone=sun.util.calendar.ZoneInfo[id="America/New_York",offset=-18000000,dstSavings=3600000,useDaylight=true,transitions=235,lastRule=java.util.SimpleTimeZone[id=America/New_York,offset=-18000000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=8,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=3,endMonth=10,endDay=1,endDayOfWeek=1,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=?,YEAR=1975,MONTH=6,WEEK_OF_YEAR=?,WEEK_OF_MONTH=?,DAY_OF_MONTH=3,DAY_OF_YEAR=?,DAY_OF_WEEK=?,DAY_OF_WEEK_IN_MONTH=?,AM_PM=0,HOUR=0,HOUR_OF_DAY=0,MINUTE=0,SECOND=0,MILLISECOND=?,ZONE_OFFSET=?,DST_OFFSET=?]

**Person Class with the dateOfBirth field* package hierarchybaseclasses;

import hierarchyinterfaces.IPerson;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Person implements IPerson {

    private String name;
    private String address;
    private String socialSecurityNumber;
    private GregorianCalendar dateOfBirth;

    public Person(){
        this.name = "";
        this.address = "";
        this.socialSecurityNumber = "";
        this.dateOfBirth = new GregorianCalendar();
    }
     public Person(String name, String address, String socialSecurityNumber, 
GregorianCalendar dateOfBirth) {
        this.name = name;
        this.address = address;
        this.socialSecurityNumber = socialSecurityNumber;
        this.dateOfBirth = new GregorianCalendar();
    }


    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 String getSocialSecurityNumber() {
        return socialSecurityNumber;
    }

    public void setSocialSecurityNumber(String socialSecurityNumber) {
        this.socialSecurityNumber = socialSecurityNumber;
    }

    @Override
    public GregorianCalendar getDateOfBirth() {
        Date date = new Date();
        dateOfBirth.setTime(date);
       // dateOfBirth.getTime();
        return dateOfBirth;
     }


     public void setDateOfBirth(GregorianCalendar dateOfBirth) {
        //Date date = new Date();
        //dateOfBirth.setTime(date);
        dateOfBirth.getTime();
        this.dateOfBirth = dateOfBirth;

    }



    @Override
    public String toString() {
        return "Person{" + "name=" + name + ", address=" + address + ", 
socialSecurityNumber=" + socialSecurityNumber + ", dateOfBirth=" + 
dateOfBirth + '}';
    }


}

Test Class This is what the instructor provided.

package hierarchybaseclasses;

import java.util.GregorianCalendar;

public class TestClassAssignment3 {   

    public static void main(String[] args) {

        // Create a date which will be used in all test methods
        GregorianCalendar testDate = new GregorianCalendar(1975, 
GregorianCalendar.JULY, 3);

        // Create a classroom 
        Classroom classroom = new Classroom("PA100", "LECTUREHALL");
        System.out.println(classroom.toString());

        // Create a Faculty member
        // Uses the date created above
        Faculty faculty = new Faculty();
        faculty.setDateOfBirth(testDate);
        faculty.setName("Elizabeth Kramer");
        faculty.setAddress("1 University Ave");
        faculty.setSocialSecurityNumber("123456789");
        faculty.setStatus("PARTTIME");
        faculty.setDateOfHire(testDate);
        faculty.setDateOfTermination(testDate);
        faculty.setSalary(10000000);

        // Create an Offered Course 
        // Uses the classroom created above
        OfferedCourse newCourseOffering = new OfferedCourse("INFO301", "Java 
Programming", classroom);
        System.out.println(newCourseOffering.toString());

        // Create a FacultyCourse (link to course id of newCourseOffereing 
created above)
        FacultyCourse facultyCourse = new 
FacultyCourse(newCourseOffering.getCourseId());

        // Add to list of courses for the faculty
    faculty.getListOfCourses().add(facultyCourse);
        System.out.println(faculty.toString());

       // Create a Student 
        Student newStudent = new Student();
        newStudent.setDateOfBirth(testDate);
        newStudent.setName("Kathy Smith");
        newStudent.setAddress("1 Beech Ave");
        newStudent.setSocialSecurityNumber("567876567");
        newStudent.setDateOfGraduation(testDate);
        newStudent.setCurrentGPA(0.0f);

        // Create a Student Course (link to course id of newCourseOffereing 
created above)
        StudentCourse studentCourse = new 
StudentCourse(newCourseOffering.getCourseId());

        // Add course to student's list of courses
        newStudent.getEnrolledCourses().add(studentCourse);

        // Add grades to Student's Course 
        studentCourse.getCourseGrades().add(90.5f);
        studentCourse.getCourseGrades().add(100.0f);
        studentCourse.getCourseGrades().add(70.5f);
        studentCourse.getCourseGrades().add(65.0f);
        System.out.println(newStudent.toString());

    }
 }

I tried to format that top bit, but it's just a disaster. I'm not sure what you're going for there. — Carcigenicate, Feb 12 '18 at 15:43
I'm not sure this comes anywhere close to a minimal example. — Mad Physicist, Feb 12 '18 at 16:30
`GregorianCalendar` is long outdated and poorly designed. The good answer is to use `LocalDate` from [`java.time`, the modern Java date and time API](https://docs.oracle.com/javase/tutorial/datetime/). The modern API is so much nicer to work with. And `LocalDate` is simpler, more natural, clearer and cleaner and matches your requirements exactly. And you won’t need anyting like the conversion between `Date` and `GregorianCalendar`. — Ole V.V., Feb 12 '18 at 20:05

giorgiga · Answer 1 · 2018-02-12T16:07:55.993

2

Look at java.text.DateFormat and java.text.SimpleDateFormat (keep in mind: instances are not threadsafe and therefore you should have local, use-once instances instead of creating static ones).

Better yet, be done with java.util for date/time and switch to java.time (your dob would be a LocalDate then)

edited Feb 12 '18 at 16:07

answered Feb 12 '18 at 15:52

giorgiga

1,758
12
29

score 1 · Answer 2 · edited Feb 12 '18 at 16:27

1

What you are looking for is not the date itself, but a short text representation of it. For that, you have to use a formatter, for example:

dateOfBirth.toZonedDateTime().format(DateTimeFormatter.ISO_DATE)

edited Feb 12 '18 at 16:27

Piotr Wilkin

3,446
10
18

answered Feb 12 '18 at 15:50

curlyBraces

1,095
8
12

Basil Bourque · Answer 3 · 2018-02-13T02:14:05.793

tl;dr

myGregCal               // Avoid troublesome legacy class.
    .toZonedDateTime()  // Convert from legacy class to modern.
    .toLocalDate()      // Extract a date-only object without time-of-day and without time zone. 
    .toString()         // Generate a String in standard ISO 8601 format.

1975-07-03

Avoid legacy classes

The troublesome GregorianCalendar class is now legacy, supplanted by the java.time classes.

`ZonedDateTime`

Convert from the legacy classes to the modern by calling new methods added to the old classes.

ZonedDateTime zdt = myGregCal.toZonedDateTime() ;

`LocalDate`

If you want only the date without a time-of-day and without a time zone, extract a LocalDate.

LocalDate ld = zdt.toLocalDate() ;

Generate strings

Generate a String in standard ISO 8601 format by default without need of a formatting pattern.

String output = ld.toString() ;

Generate a string localized automatically. Specify a Locale to determine the human language and cultural norms used in localizing.

DateTimeFormatter f = DateTimeFormatter.ofLocalizedDate( FormatStyle.MEDIUM ).withLocale( Locale.CANADA_FRENCH ) ;
String output = ld.format( f ) ;

Redefine your member variable

Your class should be redefined to use LocalDate as the type of the member variable. If you goal is to represent a date-only value, then do not use a date-with-time type. And, as mentioned above, the GregorianCalendar class is notoriously troublesome and poorly designed, replaced years ago in Java 8 and Java 9 by the java.time classes defined in JSR 310.

Dear Down-Voter, please leave a critique along with your vote. — Basil Bourque, Feb 12 '18 at 19:02

score -1 · Answer 4 · answered Feb 12 '18 at 17:40

Since you apparently don’t have experience with DateFormats or DateTimeFormatters, I’m going to suggest a much simpler approach:

String date = 
    dateOfBirth.get(Calendar.YEAR) +
    "-" +
    (dateOfBirth.get(Calendar.MONTH) + 1) +
    "-" +
    dateOfBirth.get(Calendar.DAY_OF_MONTH);

The reason for adding 1 to the month value is that get(Calendar.MONTH) does not return a month number. It returns a Calendar month constant, like Calendar.JANUARY, Calendar.FEBRUARY, …, and those constants’ numeric values are 0, 1, 2, ….

You can also use an implicit Formatter:

String date = String.format("%tF", dateOfBirth);