Discuss the below:
Create a Java application for a mail order company that uses a data entry screen in which the user types an item number and a quantity. Write each record to a file named as "MailOrderRecords.txt".
Use appropriate naming conventions, object instantiation, (where needed) accessors and mutators, and appropriate exception handling for the input. For instance, an item number may be a combination of number and letter characters, but a quantity should always be an integer.