title: JAVA writing exceptions
body: <p>I'm supposed to write exceptions to prevent invalid objects, such as Strings having no blanks or the double and int numbers being in a certain range. I am really confused on how to do this. Am I supposed to use an if/else statement? Or more try/catch statements? </p>
  
  <p>EDIT: Each object needs to be validated. The strings cannot have blanks or contain only blanks, and the numbers cannot be less than zero. There are five other try/catch statements but I only included one.  My question is what would I write so that the exception output is different for the different problems and is there a way to write it to avoid writing each exception for each separate try/catch? I looked at other posts about writing exceptions but I haven't learned what super is or does and cannot use it. </p>
  
  <pre><code>public class CD {
      String artistname = "";
      String albumname = "";
      double cdprice = 0;
      int amountinstock = 0;
  
      public CD(final String artistname, final String albumname, final double cdprice, final int amountinstock) {
          this.artistname = artistname;
          this.albumname = albumname;
          this.cdprice = cdprice;
          this.amountinstock = amountinstock;
      }
  
      public static void main(final String[] arg) throws Exception {
  
          try {
              final CD cd1 = new CD("Muse", "The Resistance", 11.99, 20);
              System.out.println(cd1.toString());
              System.out.println("=========================");
          } catch (final CDException cde) {
              System.out.println(cde.getMessage());
              System.out.println("=========================");
          }
      }
  }
  </code></pre>