Java under Mac OS X 10.7 Lion

Lion is the first version of Mac OS X that doesn't come with Java already installed. Earlier versions not only had the Java Virtual Machine or runtime element installed, but they also had the JDK installed, which is the part that lets you write your own Java programs.

Once, Java was an important part of Apple's strategy. They maintained their own version of Java for the Mac and encouraged its use by developers every bit as much as they encouraged the use of Objective-C.

The success of the iPhone and the iPad have changed that, however. Apple decided that Java would not be part of those platforms. The lack of Java is the very reason I've chosen not to get an iPhone. Instead, I get phones with Java so that I can run my own Java applications that I write for my own use.

Now that Lion doesn't have Java pre-installed, what do you do? Fortunately, a deal has been struck where Java is still available for the Mac. It's much the same arrangement as Java for other platforms. In fact, it's easier to install Java on your Mac than any other platform. And you get the JDK along with the runtime (JVM) environment.

Simply use Finder to go to Applications=>Utilities. There, start Terminal. Once Terminal starts, type in the command 'javac'. Your Mac will tell you that Java isn't installed, and let you install it.

I'm pleased that the Mac has not entirely forsaken Java, even if it's not an integral part as it has been. The basic software supplied with the Mac has declined severely over the past few years, but fortunately Java is still available and easy to install when you want it.

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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.

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Mobile Java

One of the nice things about Java is that is supported on more than desktop platforms, and has been for a long time. This means there is not only a large library of existing software, but also well-tuned development systems to use with mobile platforms.

By "mobile platform", I'm referring to smartphones and tablets. There are other mobile platforms, but these are the most common ones. Netbooks may also run a "mobile" operating system, or they may run a normal desktop OS. Those that run a normal desktop OS will run normal Java SE applications. Java SE is "Java, Standard Edition", the version that typically runs on a desktop or laptop computer.

Java ME is Java, Mobile Edition. It runs on most smartphones, and many tablets. It is very similar to the Java SE version covered in most of my articles. In fact, it is possible to write many applications using a subset of Java that will run without change under both Java SE and Java ME.

But normally a Java ME application will use user interface objects and interfaces that are specific to Java ME. In many ways these are more sophisticated than the ones for Java SE. Creating many types of graphical interfaces, such as tiled graphics, is easier in the mobile edition than in standard Java.

I have been writing small, simple applications for my cellphones for about ten years now. It's nice to be able to write your own little application for your own unique needs. I started writing Java applications for my Nokia 3650, called a "feature phone" at the time I got it. It was a Symbian Series 60 phone that ran an early version of Java ME with a very basic library of GUI features.

My next phone was a step up the Java ladder. It was a Sciphone G2, a fake Android phone. I didn't mind that it was "fake", it ran a real version of Java ME with updated GUI capabilities, which made it far easier to write applications for.

My current phone is a Blackberry Curve 8900. It runs Java ME with all the latest bells and whistles, plus a lot of Blackberry add-ons that make it easy to access the phone's features.

With my Nokia, I had a special Java development environment provided by Nokia that included a simulation of my phone, so that I could see how my programs would run before I put them on the phone. With the G2 I was on my own. I ran a standard Java ME development environment from within Eclipse, a great Java integrated development environment. The version linked above is a version specific to Java ME.

Now I'm back to having a development environment provided by my phone's maker. I have a program that simulates my phone on my computer, which again allows me to try out my programs before I put them on the phone (with my G2 I tested them as well as I could, then loaded them on the phone and hoped for the best.) It is build on Eclipse, so it is still very familiar. There is also a slew of information on the Blackberry site (linked above) about Java development.

Unfortunately, the tutorials on the site don't exactly match the actual current version of the software, but it's close enough it's not too hard to figure out. One thing that confused me, however, is the installation instructions. I thought I had to install the version of Eclipse they called for before installing the "Blackberry Java Eclipse Add-On". It's an add-on, right?

Well, it turns out that the "add-on" from Blackberry is actually the entire thing, Eclipse and all. So you just need to do that one download to get the development environment. Then download the simulator for your phone and any others you want to test your software on. Finally, apply for a signature key to make it so that you can "sign" your software to allow it to be installed on the phone through the software manager or Over The Air (OTA) when using the Blackberry-specific libraries.

If you'd rather not do this, you can develop software using a plain-jane version of Java ME, then transfer the software to your phone however you please. I put the software I developed for my Sciphone G2 on the memory card for my Blackberry, and it runs just fine.

Translating applications between Java SE and Java ME can be simple for ones with minimal amounts of graphics, like programs that mainly use text, buttons, and text entry boxes for communication. Things like games, with a more involved use of graphics, take more effort to translate between the two versions of Java. For these, I usually re-use the game logic code without changes, then rewrite the graphical display parts of the program from scratch. Because I use good object-oriented coding practices (most of the time), this isn't too much effort.

Java ME applets are easy to translate, though I write almost all of my Java software as applications now.

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Should I Still Learn Java?

With all the controversy surrounding Java thanks to the purchase of Sun by Oracle, the lawsuits flying back and forth over the Java Community Process, the Apache Foundation, Android, and all the rest,
  
does it still make sense to learn Java?

After all, the demise and abandonment of Java is being predicted practically every day.

I say Yes, now is the time to learn Java. No matter what your programming skill or background, Java is a valuable language to learn, it will be used and useful for a long time to come.

Never a Dull Moment

The Java language has been a-swirl in controversy since its public announcement. It has not become "the" language in many of the areas it originally claimed to be "the" language to use, but yet it has become popular in many other areas. In fact, Java is neck and neck with the language C for being the most popular computer language:

TIOBE Software Community Index (of most popular programming languages.)

langpop.com Programming Language Popularity Rankings.

Devtopics.com Most Popular Programming Languages.

Why Popularity Matters

Why does popularity matter? Because it entrenches a programming language, not just for now, but for many years to come. In fact, every language that has ever become deeply entrenched is still with us, so there's no way of knowing just how long popularity will keep a programming language alive.

When I was first learning to program, the big languages were assembly (the "real" programmer's language of the time), BASIC, FORTRAN, and COBOL. Every single one of those is still a viable language today. Though if you'd asked me then, I would never have thought COBOL would still be with us today. I would never have believed how popular it is, either.

But COBOL was re-invented in the late 80's. And there were a lot of big-money installations running on it. ADA failed to displace it. It's still here, and it's still a valuable part of a programmer's resume for many jobs.

FORTRAN is a language I expected to re-invent itself. It had already done so by the time I learned it (I first programmed in the original FORTRAN, but FORTRAN IV was already in common use.) But with the promulgation of Pascal, Modula-2, and C in the 80's I figured FORTRAN would be pushed into the recesses of obscurity. I was wrong.

Modula-2 was mishandled by the company that owned the rights to it, so it never took off as well as it might have. Pascal took off even though it was never intended to be anything but a classroom language. C took off since it didn't have Modula-2's licensing disadvantages and it had enough of its advantages to become the "next generation language" of its day.

Modula-2 is still with us, but it's insignificant among languages today. Because it never got popular. The others I mentioned got popular, and they're still popular today. Yeah, even Pascal. You could learn Pascal today and do a lot with it (though I don't recommend it unless you want the academic challenge of broadening yourself as a programmer.) I still write software in Pascal, though mostly for my own use, and only for older computer systems.

The key to a programming language's longevity is popularity. Once a language becomes sufficiently popular, for all practical purposes it will never die.

Java is that popular.

The Many Javas

Java has become deeply ingrained into the modern computer infrastructure. Not only does the Java Virtual Machine support a lot more languages than Java itself, but Java has spawned other languages so close to itself that if you know Java you can pick up the other languages without significant effort. C# is the most popular of these spin off languages.

Plus, there are different versions of Java. The Mobile Edition, used on cell phones, smart phones, and PDAs, is a major programming language for these platforms. Each of these platforms has its individual programming suite, and associated language. Their second language, the Esperanto of the portable world, is Java. Programmers that want their software to move easily between platforms often choose to write their code in Java.

The use of Java on servers is rife as well. Java Enterprise Edition became the most popular use of the Java language when Java was still struggling to be used as an applications programming language over a decade ago. Some say that Java on the server saved the Java language. Certainly this is what makes Java a good language to learn for professional reasons.


The Most Important Reason

The most important reason to ignore all the hullabaloo about Java's impending demise and not worry about learning it is that:

• it is a good language that's fairly easy to learn,


• expressive enough to do a lot of different things effectively,


• easy to develop sophisticated modern programs in


• without too much work for an individual or small group of developers,


• gives access to all the important parts of the machine (graphics, sound, filesystem, peripherals)


• and what you learn travels well to other languages when you go on to learn them.

It's not going to go away any time soon. There's too much momentum. There's no need to worry. Ever since the launch of Java I've heard that it's going to be gone or unusable tomorrow. History shows that just doesn't happen to popular programming languages.

If you learn Java now, you may still be using it 20 years from now. Or 30.

When I sat down to a card punch to write my first program 38 years ago as I write this, the computer lab know-it-all came to look over my shoulder.

"FORTRAN!" he said. "Why are you wasting your time with that language? It's a dead, old language. Did you know it's the oldest computer language? If you really want to be a programmer, you should start right out in BAL*! That's what real programmers use, and you're going to be behind if you waste your time on anything else."

FORTRAN doesn't make the "top 10" in programming languages much any more, but it gave me a good start. It's still among the most popular languages, around #20, or just out of the top 10 if you only count general purpose programming languages (that is, not counting scripting languages, query languages, application-specific languages, and so on.)

And learning FORTRAN never kept me from learning structured languages, AI languages, Object Oriented languages, and so on. Even though my first program included the "dreaded" GO TO statement.

There's never been a better time to learn to program. And there's never been a better time to learn Java (the language is in the best shape it's ever been!)

*Basic Assembly Language, a version of assembly language for IBM computers.

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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.

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Mini-Review: Beginning Programming in Java for the Absolute Beginner, 2nd edition, by John P. Flynt, Ph.D.

For non-programmers looking to make the transition to becoming a programmer, this book is a fine place to start. It works well as both a self-study text, and as a classroom textbook.

There aren't a lot of Java books out there written to teach the language to non-programmers. In many ways the Java language was created for C programmers, and most of the available books are written for the same audience--programmers familiar with C or C++. To my knowledge, there are presently only two books that are generally available intended to teach Java to the non-programmer. Edit: since this was written, several more books of this type have come out. The situation is far better now!

The First Step is Always the Hardest

As appropriate for a beginner's book, this book starts with a fair amount of detail on how to get set up and get started. It's challenging to strike the right balance with this material, some beginners get up and running with a minimum of effort, others run into trouble from unanticipated sources--leaving them in a position where almost no amount of information seems like enough. I think this book strikes a good balance, referring to external sources for supplemental material. Best of all, it maintains a platform-agnostic approach. You would think this is a given in a book teaching a platform-agnostic language, but it's not.

As appropriate for a beginner's book, the book teaches the principles of programming first, and Java second. The exercises of the seven chapters take the form of console, or command-line applications. Graphical applications are introduced about 2/3rds of the way through the book, in chapter 8. Most of the examples take the form of simple games.

The book teaches the basics of programming--variables, operators, flow control and such--in the first four chapters. The pacing of this material is very good, it teaches enough to not only cover the absolute core but some of the extra twists, and moves through it before it becomes tedious. Chapters five through seven get into object-oriented programming. The placement of this material in the book is great, going any further without introducing the material would be a bad idea, and any sooner would have been confusing to non-programmers.

Comprehensive Coverage

Overall the book covers a lot of ground. Someone working through this book from beginning to end is going to come out with a strong knowledge of a lot of Java. Each chapter ends with a number of exercises, which are essential additions to the examples in the text for the student to have the ability to really synthesize the information and go from program copier to a writing their own programs.

The breadth of the coverage is one of the books' strongest points. The material is well-paced, and the many complete examples of working programs are a huge advantage over the snippets that many books rely on. Exception handling, class creation, and many other subjects are covered. About the only thing I could ask for that isn't here is a brief introduction to threads, but I wouldn't even consider the idea of adding this if the book wasn't already so comprehensive.

Errata

One of the problems this book has is the typos in the program text. They are not numerous, and often even beginners can see the flaws once they know to look for them. They aren't common, only a few of the programs have errors in them. But they can be frustrating when they occur for those who are learning on their own.

Reaching Too Far?

Some of the examples try to do a bit too much, too. Rather than concentrating on one key point they add several new items at once. The centerpiece of each program is always the subject of the lesson, but additional little items get slipped into the examples. It's also worth noting that the examples that use special characters don't account for the configuration of the Terminal in Mac OS X that interferes with using these characters in the same fashion as on other platforms.

The later examples in the book also tend to get quite long. This results in a lot of typing by the beginner before they see any results. Likewise, this ties into the problem with many exercises not concentrating on the specific subject of the lesson. Particularly when graphics are introduced, I would have liked to see very short, focused examples that do only the absolute minimum to open a window and do some drawing, then add other interaction (such as the mouse, keyboard shortcuts, widgets, etc.) piecemeal. I ended up using my own example programs in my class to introduce graphics, and it went considerably smoother than I have had it go with students that followed the book alone. (I will be posting these examples in this blog when I get into graphics.) I would also like to have seen graphics introduced earlier in the book, allowing more examples to use graphics. This would also start the student making what look like "real applications" in the modern environment earlier in the learning process.

Summary

I feel this is a great book for a new programmer. Further, Java is a great language for a new programmer. Groovy may be better, but the resources available for a beginning programmer are still slim at this point, and I haven't actually had the experience of teaching it to beginners yet. Edit: There are many other languages that run on the JVM now, the others that can access the graphics and sound facilities natively (rather than through special calls to access Java syntax) would also be good candidates.

Final Grade: 85%, B

Pros:
Good material and pacing, (mostly) fun examples.
Covers lots of Java, and does it well.
Platform-agnostic.

Cons:
Typos in examples.
Discussion gets dry in places.
Examples in the later parts of the book are long and do too much at once.

Recommendation:
Buy if you're a non-programmer looking to become a programmer and want to do it with just one book. If you're willing to work out of more than one book, you may also want to consider Beginning Programming with Java for Dummies by Brad Burd (I'll be posting a mini-review of this book soon.) This also makes a good textbook for teachers looking for a class textbook thanks to the organization of the book and the chapter exercises.

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