I've attached a zipped NetBeans project that contains all the worked exercises combined into a single project.
I encourage you to attempt the problems yourself before "peeking" at the solutions.
The solutions I've provided are just one of many possible ways to achieve the same effect. If your code is different, but still works, it doesn't necessarily mean that you are "wrong". In fact, your solution may be better than the ones that I have provided. I suggest looking at the differences and understanding why you and I have made different design choices.