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.

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. :)

Embedded Java

Embedded Java sounds almost like an oxymoron. Taking a high level, large, interpreted language like Java and using it in an application field dominated by assembly and C certainly seems odd. But it's a reality.

For one thing, the microcontrollers of today are not the limited 1K to 2K ROM, 8-bit, 200kHz machine cycle rate CPUs of yesteryear. They're more powerful than the desktop systems of 10-15 years ago in many cases. And we were playing Quake II on those. So maybe Java isn't quite such a stretch, after all.

NanoVM is a small, subscale Java-ish virtual machine that runs on tiny 8-bit microcontrollers like the AVR ATMega8. It's not a full Java, but it covers most of what's interesting to the microcontroller programmer.

The JStamp is a Java development system for the aJile micros. It's also not a full Java SE implementation (what would you do with the extra bits, even if it was?), but it is a verifiable real-time Java system for embedded development.

Also, IS2T has MicroEJ, another embedded Java for a number of processors. Everything from the basics of execution and I/O up to GUIs, SOAs, and safety-critical libraries are available.

I still remember when it was considered laughable to consider a C-language embedded development system. But it has either nudged assembly out of the top spot for embedded development or is close to it, now. Any language that is popular enough can be brought to the task now, and Java is no exception.

It's all just a bunch of ones and zeroes in the end.

Greenfoot Java Programming Book

There's a book on programming in Java with Greenfoot coming out soon.



You can see a preview at the book's site, along with resources for students and teachers.

This book isn't just for class use. Greenfoot is a great way to learn to use Java. You can learn the basics of programming with graphics and sound that are far easier to use than in standard Java. Greenfoot and BlueJ both illustrate basic concepts of Object Oriented programming in a way that makes them clearer than any other method I've seen. You can deal with objects as objects, see what their member methods and fields are, and use them outside the program itself.

So, if you're in a class or self-taught, I recommend using Greenfoot along with the online resources, and this book. The book can be completed in a short time and leave you ready to write your own programs with Greenfoot, or move on to using Java without Greenfoot if you wish.

Greenfoot Results

I've posted an entry on my general blog about the results I saw from a semester with Greenfoot.

While Greenfoot was not as smooth and easy to use for beginners as I could hope, it was still a very valuable tool for the class. Both it and BlueJ are excellent ways of being introduced to some of the basic concepts behind object-oriented programming. Objects, inheritance, members, etc. are all right there for you to see and interact with, which does a heck of a lot for making things clearer.

I'd like to see BlueJ's codepad come over into Greenfoot. The student I had in individual study using BlueJ and Objects First as a text got a lot out of the codepad.

I'm planning on spending more time with Greenfoot soon, to get a better idea of what could have been done to successfully implement ideas from class that didn't work out. We had our share of frustrations, but at this point I couldn't say whether they were the result of our shortcomings or opportunities for Greenfoot to improve.

Check out the post linked above. The student all got their games in a playable state and posted at the Greenfoot Gallery, which is a huge axchievement (I did not expect 100% success on that count!) They're linked, as are the students' development blogs.

Mini-Review: Beginning Programming with Java for Dummies by Barry Burd

Of the books currently available, this one is my favorite for teaching non-programmers the basics of programming. This is in spite of the fact that it goes against a few strongly-held opinions of mine. I have worked through the book myself, and had a student with no prior programming experience use the book for self-study. So the opinions here are based on my own experience as an instructor and the feedback I've gotten from the student.

The writing style of this book is fun and easy to read. This is always a big plus for books that teach a complex and unfamiliar subject. The material is also varied from chapter to chapter, meaning that you won't be going to sleep writing different kinds of loops for three straight chapters. Subjects are interleaved, for example, there is a section on using files that breaks up material on loops and iteration.

The start of the book is quite leisurely. This is valuable in a book for non-programmers, I feel. The pace of the book picks up as it goes, so don't be fooled into thinking the book is just a brief tutorial that's been padded out into book length. The early sections are also quick reads, and sections on installing Java can be scanned or skipped over as appropriate. The pages dedicated to installing the JDK are there for a good reason, though. My experience is that just getting the JDK installed and running is one of the biggest hurdles for non-programmers who want to learn Java.

The differences I have with this book are few, but significant. The first is that graphics are left until the very tail end of the book. As I've stated elsewhere, I'm a proponent of teaching graphics early. I feel they're a good motivator for new programmers, and they allow new programmers to visualize the effects of their program's flow control structures in a way that rows of numbers can't equal.

The second difference I have with this book's approach is the use of an integrated development environment (IDE) right from the start. I've also commented in a prior article why I think it's a good idea to at least be familiar with common command line operations before starting with the IDE. I feel that starting with an IDE right off glosses over some skills that are crucial to programmers at any skill level.

The third concern I have with the book is that it recommends the use of a Windows-only IDE for use with the book. Now, if this were a .Net book or something similarly tied to a single platform I wouldn't have any problem with this. But this is a Java book! Why not a good multiplatform IDE written in Java? It's not like there aren't any good choices. My student was working on a Mac, and was able to complete the work in the book with no problem using, primarily, Arachnophilia but also using BlueJ for the latter part of the book.

I would also be concerned that people seeing the recommendation of a platform-specific IDE early in the book would think that therefore the book itself contains a substantial measure of platform-specific content. It doesn't, but flipping through the start of the book isn't enough to make that clear.

The focus of the book is on the basics of programming. It does not dip heavily into object oriented programming. It simply uses Java and its facilities to teach introductory programming in much the same way as one might use C or Pascal for the same purpose. I don't yet consider this a problem, though Greenfoot may convince me that objects and classes should be right up front now. However, I feel that starting with this book and then moving on to other resources like Greenfoot and Head First Java to develop a better understanding of Java and object oriented programming is a perfectly acceptable way to learn.

Even with its problems, I consider this book to be the best on the market for a non-programmer. It does not go as deeply into Java as Beginning Programming in Java for the Absolute Beginner, but it's an easier read and overall I like the structure better even though it covers less.

Final Grade: 90%, A

Pros:
Easy to read.
Good pacing of material.
Doesn't get boring.
A very good introduction to programming.

Cons:
Uses an IDE, and recommends a Windows-specific IDE (though any multiplatform IDE will work.)
Graphics are left until the very end.
Limited scope, but it's easy to go on from here.

Recommendation:
Get it if you're a non-programmer looking to learn how to program. You may also want to get the "next" Java book you plan on using at the same time, and start referring to it as you work through this one. You should consider downloading Greenfoot then going through its tutorials to get a grounding in classes and objects. You'll also want to get a multi-platform IDE for Java, even if you are on Windows. You may decide to use Greenfoot for this, or BlueJ or Arachnophilia (or perhaps even Eclipse or NetBeans, if you have a mentor to help you get started with them.)

Killer Java IDEs for Beginners: Arachnophilia

Arachnophilia was once one of the leading Windows-only IDEs for web page development. Now, it has grown. It's written in Java, so it runs on any current system. It also has grown to support far more than HTML. It also supports Java and a slew of other languages.

It's simple and easy to use, but very powerful. It does syntax highlighting, recognizing Java's keywords, strings, and so on, making it easier to see mistakes when entering programs. It will also match parentheses, brackets, and braces for you, making it easier to avoid--or find--errors in your program there.

Arachnophilia has a great code beautifier built in. So if you're in the practice of not always doing all the indenting you might when you first enter your program, it will go through and clean up the program with all the proper indenting and newlines to make it look really nice.

The interface is easy to configure. You can add new buttons to your toolbar, and make new buttons that do specific tasks the way you want them to. If you want a single button that backs up your old source file, saves and compiles the present one, then runs it with specific java command line options, you can make it moments with Arachnophilia.

If you work with more than Java, having one IDE for all of them is convenient. For example, if you're working with HTML and CSS as well as Java, and maybe doing some JavaScript or python on the side, you can use Arachnophilia for all of them.

My only complaint with Arachnophilia is the lack of inbuilt printing functions. But this is a minor concern. Also, if you're a Mac user, you may find it odd to be using the control key for keyboard shortcuts rather than the Apple/Command key.

Arachnophilia is the IDE that I use with my high school classes, as I mention on my other blog. I use it myself, especially on my little ASUS Eee computer which has limited screen space and not a lot of storage space. It's not an IDE that's just good for classwork. It's good enough for real work.

Give it a try.

Killer Java IDEs for Beginners: BlueJ

BlueJ is an integrated development environment created especially for new programmers learning Java. It's built to be easy to use, but also to provide powerful features to assist new programmers learn object oriented programming without headaches.

It shows a graphical representation of the classes and objects in a program. It also teaches the use of program comments for automatically generating documentation for the program. And this all happens easily without any hoops to jump through. It's just there, and it does its thing.

It also gives quick and easy access to the API documentation for Java, making it easier to use and get familiar with. Because the same documentation format will be used for your own programs, how this format works will become clear really quickly.

The BlueJ site has some great tutorials doing fun things with Java and BlueJ. There's nothing like doing interesting exercises to make learning easier.

When you're ready to move onward and upward, BlueJ can be used with NetBeans, a considerably more sophisticated, and complex, IDE for Java. So BlueJ is not a classroom-only dead end.

Learning to program has never been easier. The many resources for Java make it a great way to start programming. BlueJ is a big part of making Java a great place to start. Check it out.

The Java Virtual Machine: Adapter Cables for Your Computer's Insides

One of the problems programmers have is that different computer systems all require different ways to program them. Each computer has its own way of doing graphics and sound, its own way to talk to the keyboard and mouse, and so on. So a program written for one system wouldn't run on another.

We used to have this problem with the hardware on computers, too. If you had a Windows computer and an Apple display, they wouldn't hook up to each other. Apple computers and PCs used different video connectors. The keyboards and mice also had different connectors. The same was true of Unix workstations. They had their own connectors for their monitors, keyboards, and so on, and the connectors for Sun workstations were different from those for HP workstations.

While the outsides of computers are pretty standard now--you can hook up a PC monitor to a Mac and vice versa, the same for USB keyboards and mice--the insides are still just as weird as the outsides used to be. Each computer maker has their own connection for programs that want to talk to graphics, sound, keyboard and mouse, and so on.

Back in the old days we could hook up hardware from different manufacturers sometimes using adapter cables. In other cases, we had adapters that not only connected from one connector to another, but also translated the electronic signals.

For programmers that want to write programs that run on lots of different computer systems, the Java Virtual Machine (JVM) is like a bundle of adapter cables between your program and the computer system it's running on. No matter what system you are on, the JVM makes it look the same to your program:


This is why it's called a "virtual" machine. Java provides a sort of make-believe computer that we can program for. Then the JVM makes other computer systems pretend to be that make-believe computer. So programs written for that make-believe computer will run on any computer that has the JVM on it.

In this way the JVM acts like a whole bunch of adapter cables. On a Windows system it takes the oddball connector from its graphics system and adapts it to your program so that you can use familiar graphics objects and their methods. Similarly, it adapts the sound from OS X to your program, so that you can play music or sound effects. It adapts the filesystem from Unix so that you can read and write files using the same objects and methods as you would use on Windows or OS X. And so on. The JVM adapts all the major parts of a computer to your program, so that you can wrote one program and have it run on all major computer systems, rather than having to spend your time writing it over and over for different systems.

The system isn't perfect. The biggest problem has to do with how programs are "packaged" on each of the different systems. Your program will be the same, but the way you get it to act like a native program on each system for the user varies. The program itself will be the same, but it may need a "helper" file or some other item on each host system to make it look just like a program written directly for that system.

This will typically not be a concern for you as a programmer when you're starting out. And packaging your programs for each operating systems is a lot less work than learning all the ins and outs of how to program each system (or even just one of the systems.)

The JVM is such a useful tool that languages other than Java are being written to take advantage of it. Jython, for example, is a version of the python language that's written to use the JVM. It lets you write python programs that will run on any system with a JVM on it. Groovy is another such language. There's a long list of languages that run on the JVM in addition to Java.