My Java Program is not working
<p>I'm not so good at programming and can't tell why this isn't working. Whatever I input, it always go straight to the else statement.</p>

<pre><code>    public void pizzaIntro()
    {
    Scanner user_input = new Scanner(System.in);
    String user_command = "null";
    String apology = "I'm sorry it appears there has been some kind of mistake in your order.";
    System.out.println("Welcome to " + cM + " here we strive to deliver excellent services to all our customers!");
    System.out.println("The current prize for pizza is $" + bP + " and an extra $" + tP + " per topping.");
    System.out.println(); System.out.println();
    while(user_command != "exit")
    {
        System.out.print("Would you like toppings?(yes/no):");
        user_command = user_input.next();
        if(user_command.toLowerCase() == "yes")
        {
            System.out.println("Good Eat Your Pizza.");
        }
        else if (user_command.toLowerCase() == "no")
        {
            System.out.println("Well Ok Then!");
        }
        else
        {
            System.out.println(apology);
            System.exit(1);
        }
    }
    pic1.show();
}
</code></pre>
