String [] Array Error

Because you are printing the array itself, which calls the toString method of a Java Array. If you check the implementation of this method, you will see it doesn't print the actual values, but instead it will print a unique hash for that object.

Object.toString()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

getClass().getName() + '@' + Integer.toHexString(hashCode())

Now in your code change day to day[0] and use equals or equalsIgnoreCase for String comparison. == is reference equality.

if(day[0].equals("Monday")) 
    System.out.println("It is " + day[0] + " and Joe has to spend " + decimal.format(totalCost) + " on a new pair of shoes. He has " + decimal.format(money) + " left.");

First, use equals to compare strings (i.e. day[0].equals("Monday")).

Then, print day[0] instead of day.

to compare Strings you have to use equals:

if(day[0].equals("Monday"))

You're printing day, wich is an array.
Use day[0].

Because you are printing array

It should be day[0] not day

== operator checks whether the two references point to the same object or not whereas .equals() function will check the string content.

String name1 = new String("John");
String name2 = new String("John");
if(name1 == name2 )
{
  System.out.println("Both point to same object");
}
else
{
   System.out.println("Both point to different object");      
}

output is:

Both point to different object

whereas for

if(name1.equals(name2) )
{
  System.out.println("Both have same content");
}
else
{
   System.out.println("Both have different content");      
}

output is :

Both have same content

There's no error, you are printing an array in stdout instead of its elements. this is the default toString() for objects (printing memory location) printday[index] instead of printing the whole array.

Use days[0].equals("Monday");

Secondly ,instead of System.out.println(day); use System.out.println(day[0]).