Finished writing amazing code that compiles but won't run properly

Question

I finished writing this code for someone and it compiles but it does not run properly. Anyone see any problems? Any help would be gladly appreciated.
/* Program is for the Coconut Grove Palace Building. This program keeps track of the building occupants and the maintenance for each tenant using a simple menu system. */
import java.util.Scanner;
public class Grove {
private static Scanner keyboard = new Scanner(System.in);
/* Declaring values that will not change throughout the program. The plus one is so that people don't get confused */
private static final int TOTAL_BUILDING_MAX = 16 + 1;
private static final int TOTAL_FLOOR_MAX = 8 + 1;
private static final int APARTMENT_MAX = 4 + 1;
public static void main (String[] args) {
// Declare main variable
     int cocoPalace[][] = new int[2][3];
     char menuChoice;
     int aptNumber = 0;
     int floorNumber = 0;
     int totalFloor = 0;
     int totalBuilding = 0;
//Fill up the array with the original amount of 2 people per apartment
     for (int dex = 0; dex <3; dex++)
               cocoPalace[0][dex] = 2;
               cocoPalace[1][dex] = 2;     
     System.out.println("Welcome to the coconut grove palace");
//Main part of the program that is essentially the menu screen.     
     do
          //method that calculates the maintenance that will be used several times
          double buildingMaintenance = calculateMaintenance(cocoPalace);
          //Menu System using a switch command with nested for loops and other code.
               System.out.println("(A)partment, (B)uilding, (P)eople, E(x)it");
               menuChoice = keyboard.nextLine().charAt(0);
                    switch (menuChoice)     
//FIRST CASE 'A' ASK FOR THE FLOOR AND APARTMENT NUMBER AND DISPLAYS THE MAINTENANCE COST FOR IT
               case 'a':
               //Idiot proof 1
               System.out.println("Please enter floor number :");
               floorNumber = keyboard.nextInt();
               while (floorNumber > 2)
               System.out.println("Floor number must be between 1 and 2. Try again:");
               floorNumber = keyboard.nextInt();
               //Idiot proof 2               
               System.out.println("Please enter apartmentNumber :");
               aptNumber = keyboard.nextInt();
               while (aptNumber > 3)
               System.out.println("Apartment number must be between 1 and 3. Try again:");
               aptNumber = keyboard.nextInt();
               System.out.println("Floor number" + cocoPalace[floorNumber] + "Apartment number" + cocoPalace[floorNumber][aptNumber] + " : " + buildingMaintenance);
               break;
//SECOND CASE 'B' REPORTS THE OCCUPANCY AND MAINTENANCE FOR THE WHOLE BUILDING
               case 'b':
               for (int dex2 = 0; dex2 < 3; dex2++)
               System.out.println("Floor number 1 Apartment number " + cocoPalace[0][dex2] + " : " + buildingMaintenance);                    
               for (int dex3 = 0; dex3 < 2; dex3++)
               System.out.println("Floor number 2 Apartment number " + cocoPalace[1][dex3] + " : " + buildingMaintenance);                    
               break;
/*THIRD CASE 'P' ALLOWS THE USER TO CHANGE THE AMOUNT OF PEOPLE IN AN APARTMENT AND RECALCULATES THE MAINTENACE. IT IS ALSO "IDIOT PROOFED" SO THAT VALUES DO NOT EXCEED THE REGULATIONS OF THE BUILDING IT SELF */
               case 'p':
               //Idiot proof 1
               System.out.println("Please enter floor number : ");
               floorNumber = keyboard.nextInt();
               while (floorNumber > 3)
               System.out.println("Floor number must be between 1 and 2. Try again: ");
               floorNumber = keyboard.nextInt();
               //Idiot proof 2               
               System.out.println("Please enter apartment number : ");
               aptNumber = keyboard.nextInt();
               while (aptNumber > 4)
               System.out.println("Apartment number must be between 1 and 3. Try again: ");
               aptNumber = keyboard.nextInt();
               //Idiot proof 3 with the amount of people being added at the same time.
               System.out.println("How many people will there be : ");
               int amountPeople = keyboard.nextInt();
               cocoPalace[floorNumber][aptNumber] = amountPeople;
               while (amountPeople > APARTMENT_MAX || totalBuilding > TOTAL_BUILDING_MAX || totalFloor > TOTAL_FLOOR_MAX )
          System.out.print("Too many people in building. Please try again : ");
               amountPeople = keyboard.nextInt();
                    cocoPalace[floorNumber][aptNumber] = amountPeople;
               break;
     while (menuChoice != 'x'|| menuChoice != 'a' || menuChoice != 'p' || menuChoice != 'b');
//Method to calculate maintenance.
private static double calculateMaintenance(int cocoPalace[][])
     int amountPeople = 0;
     for (int dex4 = 0; dex4 < 2; dex4++)
               amountPeople += cocoPalace[0][dex4];
               amountPeople += cocoPalace[1][dex4];
               cocoPalace[0][dex4] = 2;
               cocoPalace[1][dex4] = 2;     
          double buildingMaintenance = 5000/(amountPeople);
     return(buildingMaintenance);
}

Answer 1

ok the array problem is fixed i was having a simple "one off" mistake when accessing the array.
As for the error that i keep getting. I honestly can't see where the problem with this is in code.
The it cant be equalt to nothing because this is written so that it has to equal a letter before the program actually runs through everything. Thanks again for the help
here is the error that i am getting when the program runs.
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 0
at java.lang.String.charAt(String.java:558)
at Grove.main(Grove.java:46)
Here is the code with the new corrections.
/* Program is for the Coconut Grove Palace Building. This program keeps track of the building occupants and the maintenance for each tenant using a simple menu system. */
import java.util.Scanner;
public class Grove {
private static Scanner keyboard = new Scanner(System.in);
/* Declaring values that will not change throughout the program. The plus one is so that people don't get confused */
private static final int TOTAL_BUILDING_MAX = 16 + 1;
private static final int TOTAL_FLOOR_MAX = 8 + 1;
private static final int APARTMENT_MAX = 4 + 1;
public static void main (String[] args) {
// Declare main variable
     int cocoPalace[][] = new int[2][3];
     char menuChoice;
     int totalFloor = 0;
     int totalBuilding = 0;
//Fill up the array with the original amount of 2 people per apartment
     for (int dex = 0; dex <3; dex++)
               cocoPalace[0][dex] = 2;
               cocoPalace[1][dex] = 2;     
     System.out.println("Welcome to the coconut grove palace");
//Main part of the program that is essentially the menu screen.     
     do
     //Variables intialized
     int aptNumber = 0;
     int floorNumber = 0;
          //method that calculates the maintenance that will be used several times
          double buildingMaintenance = calculateMaintenance(cocoPalace);
          //Menu System using a switch command with nested for loops and other code.
               System.out.println("(A)partment, (B)uilding, (P)eople, E(x)it");
               menuChoice = keyboard.nextLine().charAt(0);
                    switch (menuChoice)     
//FIRST CASE 'A' ASK FOR THE FLOOR AND APARTMENT NUMBER AND DISPLAYS THE MAINTENANCE COST FOR IT
               case 'a':
               //Idiot proof 1
               System.out.println("Please enter floor number     :");
               floorNumber = keyboard.nextInt();
               while (floorNumber > 2)
               System.out.println("Floor number must be between 1 and 2. Try again:");
               floorNumber = keyboard.nextInt();
               //Idiot proof 2               
               System.out.println("Please enter apartmentNumber  :");
               aptNumber = keyboard.nextInt();
               while (aptNumber > 3)
               System.out.println("Apartment number must be between 1 and 3. Try again:");
               aptNumber = keyboard.nextInt();
               System.out.println("Floor number" + cocoPalace[floorNumber] + "Apartment number" + cocoPalace[floorNumber - 1][aptNumber - 1] + "  :  " + buildingMaintenance);
               break;
//SECOND CASE 'B' REPORTS THE OCCUPANCY AND MAINTENANCE FOR THE WHOLE BUILDING
               case 'b':
               for (int dex2 = 0; dex2 < 3; dex2++)
               System.out.println("Floor number 1 Apartment number  " + cocoPalace[0][dex2] + "  :  " + buildingMaintenance);                    
               for (int dex3 = 0; dex3 < 2; dex3++)
               System.out.println("Floor number 2 Apartment number  " + cocoPalace[1][dex3] + "  :  " + buildingMaintenance);                    
               break;
/*THIRD CASE 'P' ALLOWS THE USER TO CHANGE THE AMOUNT OF PEOPLE IN AN APARTMENT AND RECALCULATES THE MAINTENACE. IT IS ALSO "IDIOT PROOFED" SO THAT VALUES DO NOT EXCEED THE REGULATIONS OF THE BUILDING IT SELF */
               case 'p':
               //Idiot proof 1
               System.out.println("Please enter floor number     : ");
               floorNumber = keyboard.nextInt();
               while (floorNumber > 2)
               System.out.println("Floor number must be between 1 and 2. Try again: ");
               floorNumber = keyboard.nextInt();
               //Idiot proof 2               
               System.out.println("Please enter apartment number : ");
               aptNumber = keyboard.nextInt();
               while (aptNumber > 3)
               System.out.println("Apartment number must be between 1 and 3. Try again: ");
               aptNumber = keyboard.nextInt();
               //Idiot proof 3 with the amount of people being added at the same time.
               System.out.println("How many people will there be : ");
               int amountPeople = keyboard.nextInt();
               cocoPalace[floorNumber - 1][aptNumber - 1] = amountPeople;
               while (amountPeople > APARTMENT_MAX || totalBuilding > TOTAL_BUILDING_MAX || totalFloor > TOTAL_FLOOR_MAX  )
                      System.out.print("Too many people in building. Please try again : ");
                           amountPeople = keyboard.nextInt();
                    cocoPalace[floorNumber - 1][aptNumber - 1] = amountPeople;
               break;
     while (menuChoice != 'x'|| menuChoice != 'a' || menuChoice != 'p' || menuChoice != 'b');
//Method to calculate maintenance.
private static double calculateMaintenance(int cocoPalace[][])
     int amountPeople = 0;
     for (int dex4 = 0; dex4 < 2; dex4++)
               amountPeople += cocoPalace[0][dex4];
               amountPeople += cocoPalace[1][dex4];
               cocoPalace[0][dex4] = 2;
               cocoPalace[1][dex4] = 2;     
          double buildingMaintenance = 5000/(amountPeople);
     return(buildingMaintenance);
}