Nieminen Juha wrote:

> Jon A. Cruz <jon### [at] geocitiescom> wrote:
> : Guess what? Those are many things that I specifically like about Java, and think
> : they help you to write good code:
>
>   I still don't understand how.
>
> :>   - The enum type has been left out:
>
> : This one is maybe so-so. I've seen it used well, but then again I've seen it
> : abused.
>
>   This is the typical answer. A feature has been left out because it can be
> abused.

> : Overloaded operators make things a lot harder to read
>
>   Again a typical answer.

> : Bad. Can be very powerfull in the hands of an expert, but then far more damage can
> : be done by it's use.
>
>   Again the "let's limit what a professional programmer can do in order to
> prevent beginners from doing something wrong" effect.
>
> : Actually, it's quite clear. In Java all primitives are passed by value.
>
>   No, it's not clear. There's nothing in the syntax that helps you see
> whether a variable is a reference or not. At least in C++ you immediately
> see from the definition of a function that "this parameter is a value and
> this parameter is a reference".
>   On the other hand, as I said in the previous article, _everything_ in java
> are references, so once you get used to that it's not so big deal (the basic
> types are passed by value, but you can see it from the type of the parameter).
>
> : Java programming mindset, it's very simple. As opposed to C++ where these would do
> : two different things:
>
> :     void F(int x)
> :     { x = 5;
> :     }
>
> :     void F(int &x)
> :     { x = 5;
> :     }
>
>   I don't understand what do you mean. It can be quite clearly seen (once
> you know the syntax, of course) that the second one changes the original
> value while the first one doesn't.
>   And by the way, the second one is impossible to do in java.

Yes. That's my point. Impossible in Java.

In use, here is how the first one looks:

x = 2;
foo(x);
// what is x? 2

and here is how the second one looks

x = 2;
foo(x);
// what is x? 5

I don't have any problem when reading the function; the problem is in reading the
higher-level code that uses the function. By just reading the higher level code, one
has no idea if the value of x is changed by foo or not.

>
>
> :>   - No templates:
>
> : Again, a very good thing.
>
>   Why? I said why it's a bad thing. You didn't say why it would be a good
> thing.

>   I have heard all those typical answers hundreds of times. I would like to
> understand them some time.

OK. I'm trying to help you understand the mindset. Remember this thread was on why
Java
programmers wouldn't be happy working in a C++ area. To a non-programmer it might seem
very similar, but the  devil is in the details.

A lot of it boils down to the point you made: the "let's limit what a professional
programmer can do in order to prevent beginners from doing something wrong" effect.

That's close, but not quite what I was saying. I had said "expert  user", not
"professional programmer". I have no problem with giving power to professional
programmers. The problem is that a huge number of them (perhaps 80-90%) are not quite
'expert' or 'guru'. And these are the programmers who may either initially create
software or come behind later to maintain software. The experts can handle the extra
stuff no problem, it's the other 80-90% of professionals who are the problem. (BTW,
I'm
taking that as a rough estimate from some studies in Code Complete, but as I have my
copy at work I can't cite specifics at the moment.)

Especially when it comes time to get the next version of your product out, and it's
been a year since the last one was touched, and the people who did that are no longer
with the company...

Regarding operator overloading, yes I think it has it's place in C++. But I have seen
it used in actual production code in ways that have actually caused real bugs and
problems for maintenance. If everyone who ever works at a company is in that small
percentage of programmers who are an order of mangnatude more productive, then good.
If
not...

Some of the problem comes from C++'s long history, over 20 years of accumulated
baggage, etc. More and more had been added on to C while keeping all (or most) of the
old way of C around also. thus templates were brought in to address some of the
initial
deficiencies of C++. Or rather to add more capabilities than the earlier C++.

If you drop the procedural approach and come at Java with a stronger OO design, then
it
is very nice. If not... it's doable, but not always pretty. As opposed to C++ where
one
can always drop back to doing basic C things and all is happy-happy.

Another thing that Java does differently is that usually you can only get a single
value returned from a method. Usually return status codes are no longer used since
exceptions can be thrown instead (another good thing that's in C++ also). Of course,
internal state of objects might get changed, but then if you need to access those
state
values you can either just access an exposed member, or call an accessor method.

Probably the main thing about Java and the Java mindset is that if applied to the
proper problems (key point - 'proper') good developers can come up with solid
solutions
in a much shorter timespan. Plus, if any decent effort is made, the later maintenance
of the program will be much less costly. Things like not having macros also help in
this area.

Interfaces in Java solve many of the problems that templates were created to address.
That's probably why I consider them not as necesary. However, there is some ongoing
debate about true generics being needed in Java.

And then there's probably a good way to sum things up. C++ is a language. Java is a
platform. C++ has done a lot to improve over C in this regard, but there are still
some
problems. Three years ago when I moved from doing occasional Java at work I was
editing
on a Windows box, building on Suns, and running on Linux. A year ago when I finally
got
Linux installed here at home, I was staying in it full time even though I was using NT
at work, and was often working from home.

--
"My new computer's got the clocks, it rocks
But it was obsolete before I opened the box" - W.A.Y.

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