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;