Re: Scala newbie.

> Sorry guys, but I somewhat feel the need to
> disillusion a bit about Scala and Java.
>
>> That depends on your purpose.
>
> Absolutely. But often the purpose is to write some
> app with UI and persistence. Scala is --at least currently--
> not in an autonomous position here.
>
>> So, I'll rephrase your question as "Is learning Scala enough,
>> or do I need to learn Java too to program in Scala?".
>
> In my opinion, at least at the current state of
> the Scala infrastructure, you have.  No way around.
>
>> Learning Scala is enough, and I think Programming in Scala
>> does a great job of doing it, but, then again, I know a lot
>> about Java.
>
> Right. And that will make us blind for so much problems of
> Non-Javaists.
>
>> There are two things about Java that you might miss, though:
>>
>> 1. The whole Java infrastructure.
>>
>> You may want to make "jar" files (or even "war" files or
>> similar stuff), run it on web servers or computers without
>> Scala installed, and things like that. This kind of stuff is
>> not covered by Programming in Scala. Then again, this kind of
>> stuff is usually learned through experience, not books.
>
> "Experience" does not mean "not books" in the sense of "no Java
> literature" or "no Java learning". It means to first take
> some literature and work through it "hands on".
> So even without "books": Without the typical "getting started"
> stuff, "tutorials" or "user manuals" you will have a BAD experience.
> You need some guidance to know where to start and where to go.
> This guidance stuff is mostly written in context of Java today.
> (Not Scala, nor Clojure, nor Groovy, not JRuby, not Jython ...)
>
>> 2. Java libraries.
>>
>> There are many, many Java libraries that you might be
>> interested in. There is no shame in that. After all, Scala
>> itself uses Java's standard library extensively, and there
>> are tons of good stuff out there. There is no sense in
>> spending days to display a simple graph of data when there
>> are libraries which will display your data in dozens of
>> different graphic formats.
>>
>> It's important that you are able to read API documents, and
>> understand simple examples.
>>
>> I don't think either of these two things require a more
>> formal Java education. If you can get by, it should be enough.
>
> You mean reading about scala.swing is enough to work with the
> Swing framework?  I doubt. At least if you want to do some
> things beyond simple basic GUIs.
>
> You mean reading about scala.io is enough to work with the
> file system?  I doubt too. You will have to learn about
> java.io.File and its tricky Java semantics, about all the
> different pluggable Reader/Writer things a.s.o.
> There is no sophisticated scala file system handling beyond
> scala.io.Source imho.
>
> And even if you could write such stuff without deep knowledge
> of the Java below, you will experience a shock when first
> trying to debug some less obvious bug.
>
> My statement: As long as a JVM-language does not completely
> replace rt.jar on user level, you will not do without Java
> knowledge. That's the "thin wrapper layer" problem of today's
> JVM-languages.
>
> Much more if you want to use tools which have Java, but not
> Scala APIs. For example try to use OOo's UNO bridge without
> Java knowledge...  No chance. And there is much more that
> you can easily Scala-fy AFTER you understood the Java stuff.
>
> After you have done all this, what big is the distance to
> "having learned Java"?  The question was not about formal
> education IMHO.  "Learning Java" just starts at a much simpler
> level.
>
> Hopefully some day much more basic stuff will be written
> originally in Scala....
>
>
> Just my 2ct
> Dirk
>
>
>