[evdmeer]

Hello,

Can someone tell me the differences (advantages, disadvantages) of making applications with project builder in objective C compared to java?

Because I want to create an application and have as little knowledge of Obj C as of Java.
But I am a little undecided in which language to program.

Thanks

[sadie]

Java suffers from being too slow, because it's emulated (or interpreted, or whatever they call it today). Any given program is likely to be three-five times slower in Java than in any native language.

Objective-C has most of the features of Java, but compiles directly to native code the same way that uglier languages like C++ do.

Java is technically cross-platform, but to use this you need to use the Swing libraries, which slow it down even more because they attempt to recreate all the widgets that native libraries like Cocoa provide already. It's the same reason Netscape 6 sucks.

In the long term, knowing any variant of C will make you a lot more employable. Most of the real programming that goes on is in *some* C-derived language, so starting with Objective-C is a smart move.

[BigEndian]

Okay, I'll bite...

In terms of features Java and Obj-C are very similar. They are both very advanced object-oriented languages, and any feature that one has over the other is generally balanced vice versa. Their syntax is also pretty close when it comes down to it.

When making an application using Apple's Cocoa AppKit both languages are supposed to have equal access, although Apple currently has more examples using Obj-C code. Therefore, you won't *lose* anything by writing in one language or the other.

In terms of speed, I think three-five times slower is a little excessive. Yes, Java is *currently* slower because it is compiled from byte code into machine code at runtime (Obj-C also takes a hit over regualar C because a lot is done at runtime). I say currently because I've recently read a number of articles suggesting that there are certain efficiencies that can be exploited at runtime in order to make Java just as fast, if not faster than compiled code.

On modern machines, the theory is, most people won't notice the difference between Java and Obj-C (things happen in 1.5 milliseconds instead of 1 millisecond).

That being said Java on OS X PB is currently pretty slow, although word on the street is that it screams on Final.

Finally, my suggestion is to stick with Java if you already know it. Even if you don't, Java is easier to learn and forces you into a lot of good OO programming habits that can be carried over to other languages.

[BigEndian]

Okay, I'll bite...

In terms of features Java and Obj-C are very similar. They are both very advanced object-oriented languages, and any feature that one has over the other is generally balanced vice versa. Their syntax is also pretty close when it comes down to it.

When making an application using Apple's Cocoa AppKit both languages are supposed to have equal access, although Apple currently has more examples using Obj-C code. Therefore, you won't *lose* anything by writing in one language or the other.

In terms of speed, I think three-five times slower is a little excessive. Yes, Java is *currently* slower because it is compiled from byte code into machine code at runtime (Obj-C also takes a hit over regualar C because a lot is done at runtime). I say currently because I've recently read a number of articles suggesting that there are certain efficiencies that can be exploited at runtime in order to make Java just as fast, if not faster than compiled code.

On modern machines, the theory is, most people won't notice the difference between Java and Obj-C (things happen in 1.5 milliseconds instead of 1 millisecond).

That being said Java on OS X PB is currently pretty slow, although word on the street is that it screams on Final.

Finally, my suggestion is to stick with Java if you already know it. Even if you don't, Java is easier to learn and forces you into a lot of good OO programming habits that can be carried over to other languages.

[sadie]

In terms of speed, I think three-five times slower is a little excessive. Yes, Java is *currently* slower because it is compiled from byte code into machine code at runtime (Obj-C also takes a hit over regualar C because a lot is done at runtime). I say currently because I've recently read a number of articles suggesting that there are certain efficiencies that can be exploited at runtime in order to make Java just as fast, if not faster than compiled code.

I've been reading those articles ever since i started with Java, and I've yet to see it working. To be fair, most of the slowdown in the Java i used was the fault of Swing, so in Cocoa it should be a lot closer to equal.

On the whole, use whatever you think you're most comfortable with. But employers like it if you know C.

[eyadams]

I've written several small Cocoa apps in both Java and Obj C, and the performance differences were negligible. I think the biggest problem with developing Java Cocoa apps is that Apple's documentation is poor (I would love to see javadoc generated documentation) and incomplete. Furthermore, the examples of Java Cocoa apps they provided with the developer tools on the Public Beta were not IMHO very well written Java apps - they looked like someone had written them first in Obj C, and then did the minimum amount of work necessary to make them compile under Java.

If you're thinking of writing Swing applications, the story is very different. Swing on OS X is slower than Cocoa apps of any stripe. But the difference in performance is no worse than it is on other platforms. I've done Swing development on Solaris, Linux, NT, and Mac OS 9, and Swing applications (and AWT applications for that matter) are always slower and often more clunky than native apps. This may improve on OS X when it is released, but frankly I don't think Swing apps are ever going to be as fast Cocoa or Carbon apps.

[ali]

As others have pointed out, Obj-C and Java are on par as far as object-orientedness and language features. If you learn one, you should have quite an easy time learning the other. The larger part of the learning curves in both is mastering object-oriented design, and learning the APIs. So either one should be fine; if you learn to program Cocoa in one, it won't take much time to start writing programs in the other.

As far as what to write a real app in... The reality today is that apps written in Obj-C are more efficient. This isn't necessarily because Java is interpreted and is slower to execute; today's just-in-time compilers are actually pretty good at getting code to run as fast as their compiled C counterparts. The main reason is that Java's design and this on-the-fly compiling ends up causing running apps to use way more memory than equivalent C or Obj-C applications. As a result, your apps will probably take longer to startup and your machine will swap more on low memory machines. This also means trying to run multiple apps simultaneously will cause you to run out of memory sooner.

But, get a machine with big enough memory and accept the longer launch time, and a Java app might very well execute most operations as fast as a pure C or Obj-C app.

Ali



[This message has been edited by ali (edited 03-02-2001).]

[clebin]

From a non-technical point of view, I would say that being able to program Java is far more useful in the real world, and it means you can build Mac apps, cross-platforms apps, applets and websites with the same language.

Is Obj-C really as elegant as Java? I might give it a go if it is, but my memories of C/C++ are too painful to ever go back.

Chris

[evdmeer]

Thank you all for your replies.

So it´s basically just about the same.
Seems like I am now involved in a project that will do objective C. So I´ll start there and probably try doing some java in the future.

regards