Detailed description:

        "Now let's take a look at the bank account and run a sample of it so you get an idea of what's going to take place.  Then we'll walk through the code. 
        First were going to bring up a window that we can type into.  I'm going into a
specific directory that is called JavaProg and into the sample's subdirectory and into the bank account directory. So I'm several levels deep inside the various directory structures. In this subdirectory is the bank account source code that we're going to be running, and there's also the bank account's class .class file, which is the byte code. 
       To run Java, we just type in the java command and type in BankAccount.  As we type it in, we must remember that when we run a program written in Java using the java command, which is called a Java application, we're going to execute it without specifying the file suffix.  So we'll just type in java BankAccount.  Once we hit enter, the program will run. 
      The Java virtual machine starts and it loads in the program and runs it.  As you 
see on the screen now, 'a' and 'b' are BankAccounts, and they have balances of $15.25 and $0.00.  Those are our initial values for this bank account.  And in the sample code, you'll see that we'll actually modify those accounts and we have two more lines.  Those are the final lines, where 'a' and 'b' now have $9.75 and $125.99. 
      It's a very simple application, but it gives you an idea that we can run some code and the code happens to be written Java.  That's our first step."