1. Which of the following are not valid Java identifiers, and why?

(a) wolVes

(b) United(there is only one)

(c) 87

(d) 5 3

(e) Real ale

(f) isFound?by

2. A class Television has the following fields:

private TelevisionManufacturer supplier;

private String code

private int screenSize; // in inches

private String type; // e.g. plasma screen

Assume that the class TelevisionManufacturer is available and that this class contains an equals method.

(a) Define a class variable, totalTVs, whose purpose is to keep track of the total number of Television objects constructed during execution of a program that uses the Television class.

(b) Declare a default constructor for this class.

(c) Declare a constructor for this class which has a formal parameter corresponding to each field.

(d) Declare an accessor method called getScreenSize whose purpose is to return the value of the screenSize field of this Television.

(e) Declare a mutator method that sets the type of this Television to a given value.

(f) Declare a method to determine whether or not this Television has been supplied by a given manufacturer.

Lab work

1. An electronics company needs to implement a simple stock control system. You are required to write a Java application which contains a class called StockItem together with a main method class called StockDemo. Information for each type of stock item consists of:

1.  inventory identifier (e.g. A654Y);

2.  quantity in stock (e.g. 350);

3.  demand rate (quantity removed from stock each working day, assumed constant, e.g. 50);

4.  re-order quantity (the size of an ordered batch of items, assumed constant, e.g 1000);

5.  lead-time (number of working days delay between placing and receiving an order for a batch, e.g. 5).

The class StockItem should include fields for each of the above data items and should also include each of the following:

1.  a default constructor that sets all fields to null or zero as appropriate;

2.  a constructor with arguments for all fields;

3.  set methods for all fields;

4.  accessor methods for each of the fields;

5.  a method to update the stock quantity when a batch is received;