Java Overloading

package sss3;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
public class Date {
private String month;
private int day;
private int year;
public Date() {
month = "January";
day = 1;
year = 1000;
}
public Date(int monthInt, int day, int year) {
setDate(monthInt, day, year);
}
public Date(String monthString, int day, int year) {
setDate(monthString, day, year);
}
public Date(int year) {
setDate(1, 1, year);
}
public Date(Date aDate) {
if (aDate == null) {
System.out.println("Fatal Error.");
System.exit(0);
}
month = aDate.month;
day = aDate.day;
year = aDate.year;
}
public void setDate(int monthInt, int day, int year) {
if (dateOK(monthInt, day, year)) {
this.month = monthString(monthInt);
this.day = day;
this.year = year;
}
else {
System.out.println("Fatal Error");
System.exit(0);
}
}
public void setDate(String monthString, int day, int year) {
if (dateOK(monthString, day, year)) {
this.month = monthString;
this.day = day;
this.year = year;
}
else {
System.out.println("Fatal Error");
System.exit(0);
}
}
public void setDate(int year) {
setDate(1, 1, year);
}
public void setYear(int year) {
if ( (year < 1000 ) || (year > 9999)) {
System.out.println("Fatal Error");
System.exit(0);
}
else
this.year = year;
}
public void setMonth(int monthNumber) {
if ( (monthNumber <= 0) || (monthNumber > 12)) {
System.out.println("Fatal Error");
System.exit(0);
}
else
month = monthString(monthNumber);
}
public void setDay(int day) {
if ( (day <= 0) || (day > 31)) {
System.out.println("Fatal Error");
System.exit(0);
}
else
this.day = day;
}
public int getMonth() {
if (month.equals("January"))
return 1;
else if (month.equals("February"))
return 2;
else if (month.equalsIgnoreCase("March"))
return 3;
else if (month.equalsIgnoreCase("April"))
return 4;
else if (month.equalsIgnoreCase("May"))
return 5;
else if (month.equals("June"))
return 6;
else if (month.equalsIgnoreCase("July"))
return 7;
else if (month.equalsIgnoreCase("August"))
return 8;
else if (month.equalsIgnoreCase("September"))
return 9;
else if (month.equalsIgnoreCase("October"))
return 10;
else if (month.equals("November"))
return 11;
else if (month.equals("December"))
return 12;
else {
System.out.println("Fatal Error");
System.exit(0);
return 0;
}}
public int getDay() {
return day;
}
public int getYear() {
return year;
}
public String toString() {
return (month + " " + day + ", " + year);
}
public boolean equals(Date otherDate) {
return ( (month.equals(otherDate.month))
&& (day == otherDate.day) && (year == otherDate.year));
}
public boolean precedes(Date otherDate) {
return ( (year < otherDate.year) ||
(year == otherDate.year && getMonth() < otherDate.getMonth()) ||
(year == otherDate.year && month.equals(otherDate.month)
&& day < otherDate.day));
}
public void readInput() throws IOException {
boolean tryAgain = true;
BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.
in));
while (tryAgain) {
System.out.println("Enter month, day, and year.");
System.out.println("Do not use a comma.");
String monthInput = keyboard.readLine();
int dayInput = keyboard.read();
int yearInput = keyboard.read();
if (dateOK(monthInput, dayInput, yearInput)) {
setDate(monthInput, dayInput, yearInput);
tryAgain = false;
}
else
System.out.println("Illegal date. Reenter input.");
}
}
private boolean dateOK(int monthInt, int dayInt, int yearInt) {
return ( (monthInt >= 1) && (monthInt <= 12) &&
(dayInt >= 1) && (dayInt <= 31) &&
(yearInt >= 1000) && (yearInt <= 9999));
}

private boolean dateOK(String monthString, int dayInt, int yearInt) {
return (monthOK(monthString) &&
(dayInt >= 1) && (dayInt <= 31) &&
(yearInt >= 1000) && (yearInt <= 9999));
}
private boolean monthOK(String month) {
return (month.equals("January") || month.equals("February") ||
month.equals("March") || month.equals("April") ||
month.equals("May") || month.equals("June") ||
month.equals("July") || month.equals("August") ||
month.equals("September") || month.equals("October") ||
month.equals("November") || month.equals("December"));
}
private String monthString(int monthNumber) {
switch (monthNumber) {
case 1:
return "January";
case 2:
return "February";
case 3:
return "March";
case 4:
return "April";
case 5:
return "May";
case 6:
return "June";
case 7:
return "July";
case 8:
return "August";
case 9:
return "September";
case 10:
return "October";
case 11:
return "November";
case 12:
return "December";
default:
System.out.println("Fatal Error");
System.exit(0);
return "Error";
}}}
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package sss3;
public class abc {
public static void main(String[] args) {
Date date1 = new Date("December", 16, 1770),
date2 = new Date(1, 27, 1756),
date3 = new Date(1882),
date4 = new Date();
System.out.println("Whose birthday is " + date1 + "?");
System.out.println("Whose birthday is " + date2 + "?");
System.out.println("Whose birthday is " + date3 + "?");
System.out.println("The default date is " + date4 + ".");
} }
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