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|Bruce Eckel's Thinking in Java||Contents | Prev | Next|
Java looks a lot like C++, and so naturally it would seem that C++ will be replaced by Java. But I’m starting to question this logic. For one thing, C++ still has some features that Java doesn’t, and although there have been a lot of promises about Java someday being as fast or faster than C++ the breakthroughs haven’t happened yet (it’s getting steadily faster, but still hasn’t touched C++). Also, there seems to be a perking interest in C++ in many fields, so I don’t think that language is going away any time soon. (Languages seem to hang around. Speaking at one of my “Intermediate/Advanced Java Seminars,” Allen Holub asserted that the two most commonly-used languages are Rexx and COBOL, in that order.)
I’m beginning to think that the strength of Java lies in a slightly different arena than that of C++. C++ is a language that doesn’t try to fit a mold. Certainly it has been adapted in a number of ways to solve particular problems, especially with tools like Microsoft Visual C++ and Borland C++ Builder (a particular favorite of mine). These combine libraries, component models and code generation tools to solve the problem of developing windowed end-user applications (for Microsoft Windows). And yet, what do the vast majority of Windows developers use? Microsoft’s Visual Basic (VB). This despite the fact that VB produces the kind of code that becomes unmanageable when the program is only a few pages long (and syntax that can be positively mystifying). As successful and popular as VB is, from a language design viewpoint it’s a mountain of hacks. It would be nice to have the ease and power of VB without the resulting unmanageable code. And that’s where I think Java will shine: as the “next VB.” You may or may not shudder to hear this, but think about it: so much of Java is designed to make it easy for the programmer to solve application-level problems like networking and cross-platform UI, and yet it has a language design intended to allow the creation of very large and flexible bodies of code. Add to this the fact that Java has the most robust type checking and error-handling systems I’ve ever seen in a language and you have the makings of a significant leap forward in programming productivity.
Should you use Java instead of C++ for your project? Other than Web applets, there are two issues to consider. First, if you want to use a lot of existing libraries (and you’ll certainly get a lot of productivity gains there), or if you have an existing C or C++ code base, Java might slow your development down rather than speeding it up. If you’re developing all your code primarily from scratch, then the simplicity of Java over C++ will shorten your development time.
The biggest issue is speed. Interpreted Java has been slow, even 20 to 50 times slower than C in the original Java interpreters. This has improved quite a bit over time, but it will still remain an important number. Computers are about speed; if it wasn’t significantly faster to do something on a computer then you’d do it by hand. (I’ve even heard it suggested that you start with Java, to gain the short development time, then use a tool and support libraries to translate your code to C++, if you need faster execution speed.)
The key to making Java feasible for most non-Web development projects is the appearance of speed improvements like so-called “just-in time” (JIT) compilers and possibly even native code compilers (two of which exist at this writing). Of course, native-code compilers will eliminate the touted cross-platform execution of the compiled programs, but they will also bring the speed of the executable closer to that of C and C++. And cross compiling programs in Java should be a lot easier than doing so in C or C++. (In theory, you just recompile, but that promise has been made before for other languages.)
You can find comparisons of Java and C++, observations about Java realities and practicality and coding guidelines in the appendices.