JNotePad was a project I embarked on in order to familiarize myself with both Java's Swing Framework as well as the overall workflow for creating UI Applications. To do this, I elected reverse engineer the features of Microsoft's Windows Notepad in order to gain a better understanding of how they work and how they were developed.

The first and most vital step in my opinion of any project is to define the scope of the project. The number one pitfall I see both green and seasoned developers make is falling victim to scope creep, where the size of what was once a simple or achievable project slowly but surely becomes neigh unobtainable. In order to ensure that I did not fall victim to this, I decided to place a strict limit on the scope of JNotePad: It will do everything Windows Notepad does, and nothing it doesn't.

Fortunately, Windows Notepad is a relatively simple and straightforward application, so within a few minutes I was able to go through every menu and sub-menu, and created a list of functionality which I would need to implement.

With the scope of JNotePad well defined, I got right to work on the implementation. I decided that the first thing I would implement would be a menu bar, as it was what many of the features were based on. Fortunately in swing, implementing a menu bar is super easy. All you need to do is create a new JMenuBar, then add any additional JMenus to it in the order you would like for them to appear. Although this sounds simple, and it is, the output is rather verbose. Once the menu bar was finished, it was time to conquer the problem of actually writing and editing text in my text editor. I began combing through the swing documentation to see what components were available for me to use and stumbled across the JTextArea component, which could be directly imbedded inside of a JFrame and allowed for the free input of text. This handled creating new files, but what about editing existing ones? When you think about it, any text file is really just some arbitrary sequence of characters, which we could represent as one String. Thus, when we load a file, all we need to do is use Java's Scanner class to parse the file as a String, which we can then pass into the JTextArea. Although simple, this solution worked brilliantly and JNotePad could now create, edit, and save all text files.

Although most of the feature implementations were fairly straightforward and went relatively quickly, I did still run into a few roadblocks. Most notably, the "Page Setup" menu. The problem I had was that I had no idea what it was supposed to do. Each time I tried clicking it in Windows Notepad, the application would simply become unresponsive, then crash. This put me at something of a crossroads: on one hand, I wanted to finish this project, on the other, I have no idea what this aspect of the project is even supposed to do. Here, I referred to the concrete scope of JNotePad I established earlier: "[JNotePad] will do everything Windows Notepad does, and nothing it doesn't". Therefore, if Windows Notepad crashes when you click "Page Setup", then JNotePad will to.

However, now knowing what I needed to do, I was left with the problem of how to do it. The naïve approach would have been to make a call to System.exit() and consider it done. However, System.exit() simply closes the program. Windows Notepad doesn't close when I click "Page Setup" -- it crashes. Thus, I would have to crash my program as well.

There was, however, one small issue with this: JNotePad was being written in Java, and thus ran on the Java Virtual Machine. It turns out that the JVM is incredibly annoying try and crash when you are doing it on purpose, so I would have to get creative. My first attempt was to write a broken recursive function in an attempt to crash via a Stack Overflow Error, but it turns out that the creators of the JVM thought of this, and added exception handling specifically for this case. I then had an idea: If I can't overflow the stack, perhaps I can overflow the memory. I created a loop that would create a giant array of empty objects, and ran JNotePad. The program stuttered, before I was finally greeted by "JNotePad has stopped responding...".

Prior to embarking on JNotePad, I had a tendency of making things that were fun, rather than functional. My solutions reflected this, they were always relatively hacky, with poor code organization and documentation. This was something I set on rectifying when creating JNotePad. I followed Object-Oriented programming paradigms to ensure that the codebase ensured organized, and wrote proper documentation using Javadocs to make any required maintenance a breeze. Additionally, I learned the true importance of planning and organization, especially when it comes to UI programming. When left unchecked, UI Code will turn into a spaghetti monster quite quickly. Overall, JNotePad is one of the most polished things I've made, and I've learned a great deal from it.