return statement error (string assessor method) java

learning java here, still a beginner. i am currently using blue jay and am getting the error missing return statement. here i have a method i am creating for getting the day of the week to return a string,i am also using the getValue() method from another class, the getValue method from my other class only returns ints, so i created a local variable to compare the values with the constants i have representing days of the week, here are my constants from my class and below that the method that im having issues with. thanks alot.

private NumberDisplay dayNumber;

public static final int NUMBER_OF_DAYS_IN_WEEK = 7;
public static final int SUNDAY      = 0;
public static final int MONDAY      = 1;
public static final int TUESDAY     = 2;
public static final int WEDNESDAY   = 3;
public static final int THURSDAY    = 4;
public static final int FRIDAY      = 5;
public static final int SATURDAY    = 6;

public static final String SUNDAY_STRING        = "Sunday";
public static final String MONDAY_STRING        = "Monday";
public static final String TUESDAY_STRING       = "Tuesday";
public static final String WEDNESDAY_STRING     = "Wednesday";
public static final String THURSDAY_STRING      = "Thursday";
public static final String FRIDAY_STRING        = "Friday";
public static final String SATURDAY_STRING      = "Saturday";



public String getDayOfTheWeek()
{
    int today = dayNumber.getValue();
    if (today == SUNDAY)
    {
        return SUNDAY_STRING;
    }
    else if (today == MONDAY) 
    {
        return MONDAY_STRING;
    }

    else if (today == TUESDAY)
    {
         return TUESDAY_STRING;
    }
    else if (today == WEDNESDAY) 
    {
        return WEDNESDAY_STRING;
    }

    else if (today == THURSDAY)
    {
        return THURSDAY_STRING;
    }

    else if (today == FRIDAY)
    {
        return FRIDAY_STRING;
    }

    else if(today == SATURDAY) 
    {
        return SATURDAY_STRING;
    } 

}