Setters method in the constructor

Question

Hi everyone;
I am having some trouble with one of my constructor. I am trying to write my constructor as strong as possible to avoid some wrong input by the user during the running time.
Therefore I decided to write setter methods and then use them in my constructor, but when I tried to test my class with JUnit, the test failed and I don't know why !
This is my code :
//CONSTRUCTOR:
      * Creates a new item with a given quantity and price.
      * The constructor use three helper methods.
      * @param itemName
      *                          enter a String for the name of the item.
      * @param itemQuantity
      *                               enter an integer for the quantity of the item.
      * @param itemPrice
      *                               enter a double for the price of the item.
     public Item(String itemName, int itemQuantity, double itemPrice) {
          setItemName(itemName);
          setItemQuantity(itemQuantity);
          setItemPrice(itemPrice);
//SETTER METHODS:
      * Set the quantity of item available in stock.
      * @param itemQuantity
      *                               enter an integer for the quantity of item.
     public void setItemQuantity(int itemQuantity) {
          if (itemQuantity > 0) {
               this.itemQuantity = itemQuantity;
          } else {
               throw new IllegalArgumentException("The amount must"
                         + " be greater than zero.");
      * Set the price of the item.
      * @param itemPrice
      *                          enter a double for the price of the item.
     public void setItemPrice(double itemPrice) {
          if (itemPrice > 0) {
               this.itemPrice = itemPrice;
          } else {
               throw new IllegalArgumentException("The price must be "
                         + "greater than zero");
//JUNIT TEST:
      * Create a new object item.
     private Item item;
      * Set up the test by initialising the new item.
      * @throws Exception (expected = IllegalArgumentExeption.class)
     @Before
     public void setUp() throws Exception {
          item = new Item("Bible", 10, 20.0);
     @Test
     public void constructor() {
          item.getItemName();
          assertEquals("Bible", item.getItemName());
          assertEquals(10, item.getItemPrice());
     }I tested my two setter methods and they work properly in normal and boudary cases.
In my Junit test, when I try to get the item price i have the error : expected IllegalArgumentException.
Does someone have an idea ?
Thank you,
Henri

Answer 1

by the way if your constructor is going to call another method (like the setters) then either the class or the called methods should be final. Otherwise subclasses could change the behavior of the constructor, which is a bad place for behavior to go out of hand.
And generally you're better off designing inheritance into the the design, such that overrideable methods are clearly defined as such and everything else is private or final.
Just my experience, YMMV, etc.