I am making an event calendar and am having issues with a "ArrayIndexOutOfBoundsException" Error. It usually pops up whenever "n" or "p" is selected in the menu a few times.

The goal of this project is to be able to input events into a calendar and then print them out into a txt folder.

import java.io.File;

import java.io.FileNotFoundException;

import java.io.OutputStream;

import java.io.PrintStream;

import java.util.Calendar;

import java.util.Scanner;

public class Assignment2 {

private static int SIZE = 15;

private static char HORIZONTAL = '=';

private static char VERTICAL = '|';

private static boolean showLine = true;

private static int dayValue = -1;

private static String[][] eventArray;

public static boolean loadEventsFromFile(String filename) {

eventArray = new String[12][];

for(int i = 0; i < 12; i++)

eventArray[i] = new String[getMaximumDays(i)];

try {

Scanner input = new Scanner(new File(filename));

while(input.hasNext()) {

String date = input.next();

String event = input.nextLine().trim();

int day = dayFromDate(date);

int month = monthFromDate(date);

eventArray[month-1][day-1] = event;

}

input.close();

return true;

}

catch (FileNotFoundException e) {

return false;

}

}

public static void drawMonth(PrintStream out, int month, int daysToSkip, int maxDays) {

for(int i = 0; i < (SIZE * 7) / 2 - 3; i++) {

System.out.print(" ");

}

if (month == 1) {

out.println("January");

}

else if (month == 2) {

out.println("February");

}

else if (month == 3) {

out.println("March");

}

else if (month == 4) {

out.println("April");

}

else if (month == 5) {

out.println("May");

}

else if (month == 6) {

out.println("June");

}

else if (month == 7) {

out.println("July");

}

else if (month == 8) {

out.println("August");

}

else if (month == 9) {

out.println("September");

}

else if (month == 10) {

out.println("October");

}

else if (month == 11) {

out.println("November");

}

else if (month == 12) {

out.println("December");

}

for(int i = 0; i < 7; i++) {

for(int j = 0; j < SIZE / 2 -1 ; j++) {

out.print(" ");

}

if(i == 0) {

out.print("SUN");

} else if (i == 1) {

out.print("MON");

} else if (i == 2) {

out.print("TUE");

} else if (i == 3) {

out.print("WED");

} else if (i == 4) {

out.print("THU");

} else if (i == 5) {

out.print("FRI");

} else {

out.print("SAT");

}

for(int j = 0; j < SIZE / 2 - 2; j++) {

out.print(" ");

}

}

out.println();

int start = 1;

while (start <= maxDays) {

if(start == 1) {

drawRow(out, start, month, maxDays, daysToSkip);

start += 7 - daysToSkip;

} else {

drawRow(out, start, month, maxDays, 0);

start += 7;

}

}

int width = SIZE *7 ;

String str = "";

for (int i = 0; i <= width; i++)

str += HORIZONTAL;

out.print(str);

out.println();

}

public static void drawRow(PrintStream out, int start, int month, int maxDaysInMonth, int skip) {

String str = "";

int width = SIZE * 7;

for (int i = 0; i <= width; i++)

str += HORIZONTAL;

out.println(str);

int day = start;

String space = " ";

out.print("|");

for (int cell = 1; cell <= 7; cell++) {

str = "";

if (cell > skip && day <= maxDaysInMonth) {

if(dayValue == day) {

str += "*" + day++ + "*";

} else {

str += day++;

}

}

while (str.length() < SIZE - 1)

str += space;

str += VERTICAL;

out.print(str);

}

int height = SIZE / 2;

day = start;

for (int h = 2 ; h <= height; h++) {

out.print(" |");

for (int cell = 1; cell <= 7; cell++, day++) {

str = "";

if(h == 2 && cell > skip && day <= maxDaysInMonth && eventArray[month-1][day-1] != null)

str = eventArray[month-1][day-1];

while (str.length() < SIZE - 1)

str += space;

str += VERTICAL;

out.print(str);

}

}

out.print(" ");

}

public static void displayDate(PrintStream out, int month, int day) {

if (showLine == true) {

out.println("Month: " + month);

out.println("Day: " + day);

}

}

public static int monthFromDate(String date) {

String tokens[] = date.split("/");

return Integer.parseInt(tokens[0]);

}

public static int dayFromDate(String date) {

String tokens[] = date.split("/");

return Integer.parseInt(tokens[1]);

}

public static void drawCalendar(PrintStream out, int month, int day) {

int startingDay = getStartingDay(month);

int maxDays = getMaximumDays(month);

drawMonth(out, month, startingDay, maxDays);

displayDate(out, month, day);

}

public static int nextGoodMonth(int month) {

int mt = month;

if (month == 12)

return 1;

return mt + 1;

}

public static int previousGoodMonth(int month) {

int mt = month;

if (month == 1)

return 12;

return mt - 1;

}

public static int getStartingDay(int month) {

Calendar cal = Calendar.getInstance();

cal.set(Calendar.DAY_OF_MONTH, 1);

cal.set(Calendar.MONTH, month - 1);

return cal.get(Calendar.DAY_OF_WEEK) - 1;

}

public static int getMaximumDays(int month) {

Calendar cal = Calendar.getInstance();

cal.set(Calendar.MONTH, month - 1);

return cal.getActualMaximum(Calendar.DATE);

}

public static void main(String[] args) {

Scanner keybd = new Scanner(System.in);

String cmd = "";

int day = -1;

int month = -1;

loadEventsFromFile("calendarEvents.txt"); //load events at start up

while (true) {

System.out.println("Please type a command");

System.out.println("\t\"e\" to enter a date and display the corresponding calendar.");

System.out.println("\t\"ev\" to enter an event.");

System.out.println("\t\"fp\" to print calendar to file");

System.out.println("\t\"t\" to get todays date and display the todays calendar");

System.out.println("\t\"n\" to display the next month");

System.out.println("\t\"p\" to display the previous month");

System.out.println("\t\"q\" to quit the progrram");

cmd = keybd.nextLine();

if (cmd.equalsIgnoreCase("e")) {

// get user input date

System.out.print("Enter a date (m/d): ");

String date = keybd.nextLine();

dayValue = day = dayFromDate(date);

month = monthFromDate(date);

showLine = true;

drawCalendar(System.out, month, day);

continue;

}

else if (cmd.equalsIgnoreCase("ev")) {

// get user input date

System.out.print("Enter an event (m/d event_title): ");

String date = keybd.next();

String event = keybd.nextLine();

int d = dayFromDate(date);

int m = monthFromDate(date);

eventArray[m-1][d-1] = event;

if (d == 1 || m == 1) {

eventArray[m][d] = event;

}

}

else if (cmd.equalsIgnoreCase("t")) {

Calendar cal = Calendar.getInstance();

dayValue = day = cal.get(Calendar.DATE);

month = cal.get(Calendar.MONTH) + 1;

System.out.println("month" + "/" + "day");

showLine = true;

drawCalendar(System.out, month, day);

}

else if (cmd.equalsIgnoreCase("n")) {

if (day != -1 && month != -1) {

day = 1;

dayValue = -1; // as user has not mentioned any value specifically

month = nextGoodMonth(month);

System.out.println(month);

showLine = false;

drawCalendar(System.out, month, day);

continue;

}

else {

System.out.println("Please display a calendar first. ");

continue;

}

}

else if (cmd.equalsIgnoreCase("p")) {

if (day != -1 && month != -1) {

day = 1;

// as user has not mentioned any value specifically

dayValue = -1;

month = previousGoodMonth(month);

System.out.println(month);

showLine = false;

drawCalendar(System.out, month, day);

continue;

}

else {

System.out.println("Please display a calendar first. ");

continue;

}

}

else if (cmd.equalsIgnoreCase("fp")) {

System.out.println("Enter month to print (1-12):");

month = keybd.nextInt();

System.out.println("Enter filename: ");

String fname = keybd.next().trim();

keybd.nextLine();

dayValue = -1;

try {

PrintStream outfile = new PrintStream(new File(fname));

drawCalendar(outfile, month, day);

outfile.close();

}

catch (FileNotFoundException e) {

System.out.println(e.getMessage());

}

}

else if (cmd.equalsIgnoreCase("q")) {

System.out.println("Program terminated...");

break;

}

else {

System.out.println("Please enter a valid command. ");

continue;

}

}

keybd.close();

}

}