Portability of Java Programming Skills

You can program in Java (or are learning to.) That's great! But what else can you do with those skills? Are you trapped with Java?

Not at all. One of the reasons I chose Java as a language for use in the classroom is that Java programming skills translate so well into skills for other languages. Here are some other languages, and a brief look at what your Java programming skills will give you in the way of a head start, and what differences to look out for.

C# (C Sharp)
C# and Java are practically the same. C#'s roots are in Java, as is the concept of its libraries relative to Java's API. The libraries differ, but if you're used to Java's API you'll have no trouble getting right into C#'s libraries to find the classes you're looking for.

The major development tools are very similar, or, in many cases, you can use the same IDEs for C# as for Java. You can also do cross-platform development in C# just as you can with Java thanks to tools like Mono (which I highly recommend as a way of becoming familiar with C#) and the forthcoming cross-platform Visual Studio tools from Microsoft.

C
Java is an object-oriented descendent from the C language. C does not have object-orientation built in, but you should have no trouble understanding much of the code. Imagine writing Java without creating your own classes, or only creating limited classes. This isn't strictly accurate, since it is possible to write object-oriented code in C, it just requires the programmer to do much of the work that Java does in their code. Providing for isolation of data, inheritance, etc. has to be performed through code written explicitly to perform these functions.

Modern versions of C, such as ANSI C/ISO C (C99) provide a version of C which makes it easier to write good code if you're coming from an object-oriented background.

Another major hurdle will be dealing with memory management directly (C has no garbage collection), and learning how to use the various functions of C which are often not as predictable as the Java methods you are familiar with.

The basics of C will already be familiar to you, but you should conduct some formal study of C and use its standard libraries extensively before seeking to start formal projects with it.

C++
C++ is another object-oriented outgrowth of C, like Java, yet it uses a very different approach. You will find that your Java experience can be very misleading with respect to the handling of data and the operation of methods in C++. Also, C++'s libraries tend to be much more platform-specific than those of Java. In Java you have platform-specific libraries, yet it is possible to write good code that does not rely on it, or that relies on it little enough to allow 90% or more of your code to be written in a non-platform-specific fashion.

With C++, however, you'll find that while there are standard cross-platform libraries, most code will be best written to the platform to which it is being compiled.

Python
Python will be very easy to learn once you know Java. Its syntax is quite different, and its approach to what is implicit and what must be explicitly defined is very different to that of Java. Conceptually, however, you will be right at home and will be able to learn the specifics of the language very easily.

Like Java, Python has extensive libraries. Some are part of Python's core distribution, but others are not. You will find that even in the core libraries there is much less cross-platform support than Python seems to promise. Also, you will need platform-specific libraries for any graphics or audio code. Even in cross-platform libraries, you will find that there are significant differences between platforms. If you are writing code that does not rely on the platform for presentation, however, (for example code that uses a browser), Python works very well in a cross-platform environment.

Javascript
Javascript is also very similar to Java in many ways, but not as much as the name of the language might lead you to believe. Java has recently acquired many of the constructs that have been favorites of Javascript programmers for years.

You will find that handling data under Javascript is very different to the means used in Java. You will also find the nomenclature very, very different, despite the similarities in the languages. This will probably be your biggest early hurdle in transitioning from one language to the other.

The best approach is to set yourself to learn the ways that things are best done in Javascript, before trying to write Java code in Javascript syntax. Once you can write solid small programs, enough will become apparent to you that you can begin to take advantage of your programming knowledge from Java to apply it to your Javascript programs. Some programming languages it is your knowledge of Java syntax and structure that will make those languages easy for you. Javascript isn't one of those languages. The payoff comes after you have learned Javascript syntax and structure, the process of designing well-build object oriented software will pay off.

With Javascript, the web browser is almost certain to be your "platform." You will need to learn the Domain Object Model to effectively apply Javascript. If you have already been using the DOM with your Java code (over half of Java code is written for the web), then you are already there. Otherwise, it's something else new you'll have to learn.

Objective-C
The transition from Java to Objective-C is far simpler than to C++. The object-oriented techniques used in Objective-C will make immediate sense to a Java programmer, as will the program structure. Objective-C requires you to do your own memory management, unlike Java, but it provides facilities to do so more simply and effectively than standard C.

The libraries will differ completely from those of Java, and your platform will almost certainly be iOS or Macintosh, so those are the platforms whose libraries you'll learn. Objective-C differs from Java more than C#, but not so much as to make it extremely difficult to transition to. After C#, Objective-C is probably the easiest non-scripting language for you to learn.

Swift
Swift is based on Objective-C, and will be even easier for a Java programmer to learn and use. Most of the changes not only make it easier to produce programs in general, but make it conceptually simpler for a Java programmer to make the transition. You'll be reading the code in the first day, and will be able to produce effective code with only a few hours of work. As with Objective-C, there are new libraries for you to learn tied to Swift's platforms (iOS and Mac), but you will find these even easier to navigate than the Java libraries that suffer from Java's early history of development being encased within them.

PHP
PHP does not have the sort of object-oriented programming facilities that you will be used to from Java, but its syntax will be easy for you to pick up. You will likely feel limited by PHP compared to Java, but PHP has a more limited purpose than Java--it is focused on web programming. While Java is heavily used for server-side web programming, it is much more of a general purpose language than PHP.

You will need to learn the specifics of PHP's syntax and data structures, but after mastering Java, you will not find this difficult.

Summary
These cover the most popular programming languages in use at this time. There are other languages, like Scala, that are specifically designed to be like Java yet address shortcomings perceived in Java, either for some specific use, or to change things that are historically embedded in Java's design. These are very easy for a Java programmer to transition to.

At present, Oracle's support of Java is limiting its market relative to the general use for Java that Sun used to promote. While Java is still widely used, and will continue to be for the foreseeable future, it always behooves a programmer to be competent in multiple languages and to have more than one set of conceptual tools for problem solving at hand. So it is good to know other languages, even if they are scripting languages like Python and Ruby.

Currently, Microsoft is in the process of making a strong play to the cross-platform development market which Java has served. With C# as part of this, and C# plus Mono (a cross-platform version of .Net) already available, it is very easy for a Java programmer to add this to their programming portfolio to gain a greater range of opportunities for work, and a wider range of tools for solving programming problems.

I highly recommend, at least, spending some time with C# under Mono or .Net if you are currently a Java programmer. I think you'll find that you feel right at home.

An advantage of learning .Net is that it will open up Windows-specific programming in C++ to you as well. The C++ language will be new, but you'll already know the libraries that you'll be using. If Microsoft delivers on their recent promises of making their tools fully cross-platform for Mac and Linux, then you'll be able to apply those skills to those platforms as well.

Mobile
Java is the language you'll use on Android, currently the dominant mobile platform in terms of users. Objective-C is the language for iOS, and it's not a huge jump for a Java programmer to make. Swift is a simplified version of Objective-C, and it is even easier for the Java programmer to learn. If you are planning to develop for iOS, it is worth making the effort to transition to a language built for it, and Swift should be your first stop.

DozCalc: A More Polished Android Application in Java

Since my post on my first Android app, I've done a lot. I went on from that first app to learn how to access a lot more of the device, deal with a wider range of circumstances, and generally get to know Android and the tools for developing for it better.

Specifically, I have posted an app for Android called DozCalc.

DozCalc is a dozenal (base 12) calculator. It doesn't convert back and forth between dozenal and decimal, so be warned. Just like your normal four function calculator that works in base 10 and nothing else, DozCalc works in base 12 and nothing else.

Java

The "programming", like development in many modern GUI environments, was less about the functional code (in this case in Java) and more about the user interface. While Android allows for UI programming in Java, it's typically simpler to implement it in XML. And this is what I did.

The only problem I had was dealing with loss of precision in some calculations. At first, I was going to be very clever and write a proper function using numerical analysis to get the value right to some specified number of fractional digits (note: it's not proper to call them 'decimal digits' when you're working strictly in base 12). However, it was simpler and easier to just add a small value to certain calculations (division, for example) to make all the fractional values come out correct. Far simpler to program, just as effective for this use, and every bit as accurate as the average four function calculator.

Sometimes programming is less about the language, or the algorithm, than about just getting a solution that's accurate enough for the need, then moving forward.

Thanks to object-oriented design, I was able to re-use the code from DozCalc in another graphical calculator. Unfortunately, I got bogged down in the graphical design, so the steampunk styled version of DozCalc (named Mr Wells' Calculator) has yet to be released, and may not be depending on how my schedule of current projects goes.

My First Android App

I ordered an Android phone about two weeks ago.

Last Thursday, I installed the Android SDK. It went smoothly, I've installed it under two versions of Windows 7, as those are my systems with the most RAM and CPU power (for the Android device emulator. My older Mac and Linux systems lug a bit when doing serious hardware emulation.)

I started the online tutorials linked on the SDK's opening page. Since the SDK is based on Eclipse (my favorite full-fat IDE for Java), it was no problem getting started.

I got a simple app, modified from the 'getting started' tutorial, running on an emulated Android device within an hour or so of starting.

The next day--Friday, my phone arrived in the mail. It runs Android 4.1.1.

After a busy day on Friday interleaved with charging and moving into the phone, I got the Android SDK talking to my phone today, downloaded an updated version of the app (a =very= simple character generator for my RPG, RoonVenture.) It ran just fine. It's very similar to my online RoonVenture Character Generator.

That is, it's ugly, poorly designed, but bone-simple while producing the essential results.

Nevertheless, I found my Java skills played right into Android development (so far):

Android's native language is Java, with some unique libraries.

The default IDE is Eclipse, a common Java IDE (and one I recommend, though I still do about half my code in something lighter, ranging from vi or vim to Arachnophilia or BlueJ.)

It's a lot like Java ME development (which I've done to build apps for my older "feature phones".)

So, if you're doing Java now, I recommend jumping into Android if the opportunity arises. I've found it easier to get started than with Java ME, Blackberry, or Nokia Series 60 development. Though it's worth noting that I'm coming to this with prior experience with all of those first.

Now I'm taking a break from the computer and reading a hardcopy book, "Creating Android Applications" by Chris Haseman. It's written for the experienced Java programmer who doesn't need 250 pages on Java and Eclipse.

That should help me make a better app next. :)