Java Generics and Collections

andrew cooke writes "Java 6 was recently released, but many programmers are still exploring the features introduced in Java 5 — probably the most significant changes in the language's twelve year history. Amongst those changes (enumerations, auto-boxing, foreach, varargs) generics was the most far-reaching, introducing generic programming in a simpler, safer way than C++ templates and, unlike generics in C#, maintaining backwards (and forwards) compatibility with existing Java code." Read on for the rest of Andrew's review.

Java Generics and Collections
author	Maurice Naftalin, Philip Wadler
pages	273
publisher	O'Reilly Media, Inc.
rating	9/10
reviewer	Andrew Cooke
ISBN	978-0-596-52775-4
summary	Guide to Java generics; also includes interesting discussion of collection classes.

Given the history of Generic Java, Naftalin and Wadler's Java Generics and Collections has a distinguished pedigree. In this review I'll argue that this is a new classic.

If you're a Java programmer you've probably heard of generics, an extension to the type system that was introduced in Java 5. They give you, as a programmer, a way to write code even when you don't know exactly what classes will be used.

The obvious example is collections — the author of a List class has no idea what type of objects will be stored when the code is used.

Before generics, if you wanted to write code that handled unknown classes you had to use make use of inheritance: write the code as if it would get Objects, and then let the caller cast the result as necessary. Since casts happen at runtime any mistakes may cause a runtime error (a ClassCastException).

Generics fix this. They let you write code in which the classes are named (parameters) and the compiler can then check that the use of these class parameters is consistent in your program. So if you have a List of Foo instances you write List<Foo> and the compiler knows that when you read that list you will receive a Foo, not an Object.

I'll get to the book in a moment, but first a little history. If you know any type theory — particularly as used in functional languages like ML and Haskell — then you'll recognize my quick description above as parametric polymorphism. You'll also know that it is incredibly useful, and wonder how Java programmers could ever have managed without it.

Which explains why Philip Wadler, one of the people responsible for Haskell, was part of a team that wrote GJ (Generic Java), one of the experimental Java mutations (others included PolyJ and Pizza) that, back in the day (late 90s) helped explore how parametric polymorphism could be added to Java, and which formed the basis for the generics introduced in Java 5.

So if you want to understand generics, Wadler is your man. Which, in turn, explains why I jumped at the chance to review O'Reilly's Java Generics and Collections, by Maurice Naftalin and Philip Wadler.

This is a moderately slim book (just under 300 pages). It looks like any other O'Reilly work — the animal is an Alligator this time. It's well organized, easy to read, and has a decent index.

There's an odd discrepancy, though: Wadler is the generics Guru; this is going to be `the generics reference'; generics are sexy (in relative terms — we're talking Java here) and collections are not; the title has "Java Generics" in great big letters with "and Collections" in little tiny ones down in a corner. Yet very nearly half this book is dedicated to collections.

Generics is a great, practical read. It starts simply, introducing a range of new features in Java 5, and then builds rapidly.

If you are completely new to generics, you'll want to read slowly. Everything is here, and it's very clear and friendly, but there are not the chapters of simple, repeated examples you might find in a fatter book. Within just 30 pages you meet pretty much all of generics, including wildcards and constraints.

If that makes your head spin, don't worry. Read on. The next hundred or so pages don't introduce any new syntax, but instead discuss a wide range of related issues. The chapters on Comparisons and Bounds and Declarations contain more examples that will help clarify what generics do. And the following chapters on Evolution, Reification, and Reflection will explain exactly why.

So the first seven chapters introduce generics and then justify the implementation — any programmer that takes the time to understand this will have a very solid base in generics.

There are even some interesting ideas on how Java could have evolved differently — section 6.9 Arrays as a Deprecated Type presents a strong case for removing arrays from the language. It's a tribute to the clarity and depth of this book that the reader is able to follow detailed arguments about language design. Fascinating stuff.

The next two chapters, however, were my favorites. Effective Generics and Design Patterns give sensible, practical advice on using generics in your work, including the best explanation of <X extends Foo<X>> I've seen yet (so if you don't know what I am talking about here, read the book).

(A practical word of advice — if at all possible, use Java 6 with generics. Java 5 has a sneaky bug).

The Collections part of the book was more along O'Reilly's `Nutshell' lines: the different chapters explore different collection types in detail. I must admit that at first I skipped this — it looked like API docs re-hashed to extend the size of the book.

Then I felt bad, because I was supposed to be reviewing this book (full disclosure: if you review a book for Slashdot you get to keep it). And you know what? It turned out to be pretty interesting. I've programmed in Java for (too many) years, and I guess I've not been quite as dedicated to tracking how the library has changed as I should have been — I learned a lot.

Again, a wide range of readers are welcome. This is more than a summary of the Javadocs, ranging from thumbnail sketches of trees and hashtables to a discussion of containers intended for multi-threaded programming.

The way I see it now, this part is a bonus: the first half, on generics, makes this book one of the standards; the second half is an extra treat I'm glad I stumbled across (I guess if you're some kind of weird collection-fetishist maybe it's even worth buying the book for).

I've used generics since the first beta release of Java 5 and had experience with parametric polymorphism in functional languages before that (in other words, I can tell my co- from my contra-variance). So I guess I'm heading towards the more expert end of the spectrum and I was worried I'd find the book boring. It wasn't. After claiming to be expert I don't want to spoil things with evidence that I'm actually stupid, but reading this book cleared up a few `misunderstandings' I'd had. I wish I had read it earlier.

If you're new to generics, and you don't mind thinking, I recommend this book. If you're a Java programmer who's a bit confused by <? super Foo> then this is the book for you.

The only people who shouldn't read this are people new to Java. You need to go elsewhere first. This is not a book for complete beginners. This is a great book in the classic — practical, concise and intelligent — O'Reilly mould.

---

You can purchase Java Generics and Collections from amazon.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Generics are basically good.

But it can in some cases be tricky when you get a really complex structure of Vectors containing Vectors containing Comparables. Not that it's impossible, but it can be a challenge.

One thing that I found in Java5 was that it lacked generics for several cases, e.g. Awt/Swing objects that were able to contain Object themselves. Not that it was a big problem, but it wouldn't have been bad to have that support there too...

Anyway - Generics is one of the best features of added to Java lately. It really helps. How I miss it when I'm programming for J2ME...

All I really wanted...

... was a quick and dirty intro to Java generics. I've had trouble finding that on Sun's site (especially ones with good code examples), but Google returns some good results. Given the availability of free tutorials, I probably wouldn't buy the book just for that.
That said, this sounds like a good resource on Java Collections in general (though Sun's javadocs are pretty nice themselves), as well as the other features introduced in Java 5. There also seems to be some discussion of more complex generic structures.
I'm still a bit lukewarm about buying it, but if I were getting back into a lot of Java stuff, I probably would.

Java 'generics' are not real generics

Java generics are not real generics, then you parametrize a generic class in Java you don't really create a new type. You just attach some information for Java compiler so it can perform automatic casting and save you some typing.

Java generics don't provide real type safety, for example, you can easily put Strings in List (that's why Collections.checkedCollection kludge was added).

In C# (or C++), on the other hand, parameterizing a generic type creates a _new_ _type_ which guarantees type safety and allows some quite interesting tricks. For example, in C# generics can be parametrized by primitive types and structs (which don't exist in Java, anyway) so you can have List without overhead of boxing. That's impossible in Java.

Re:Java 'generics' are not real generics

Sure, Java generics work at compile time instead of runtime. At runtime, you can do whatever you want. But it's still true that Java generics provide a much safer interface which prevents a wide field of bugs, and which makes code much more readable. I think it's obvious that

l = new List();
l.add(foo);
Foo foo = l.get(0);

is much safer and easier to read than

v = new Vector();
v.add(foo);
Foo foo = (Foo) v.get(0);

especially when you consider that the obvious mistake

v = new Vector();
v.add(bar);
Foo foo = (Foo) v.get(0);

throws a cast exception at runtime.

I've read a lot of complaints that type erasure (the means by which Java generics are implemented) doesn't solve the whole problem. But there was a certain class of program that generics solved, and it has made development in Java much more productive and safe.

Re:Java 'generics' are not real generics

Java generics don't provide real type safety, for example, you can easily put Strings in List (that's why Collections.checkedCollection kludge was added).

I've never understood this objection. This will always generate a compiler warning, and depending on your compiler settings may not even compile successfully. The only time you might turn those warnings off is when you're having to deal with non-genericized legacy code.

Re:Java 'generics' are not real generics

What you are missing is that it's a *good* thing that Java generics are not "real" generics.

With "real" generics the system has two choices: either generate lots of bloated specific instances of the code, or add type-checking at runtime. CLR designers thought they were going to do the former and it was going to be 'uber leet' and fast, but found out it's not practical (most of the optimizations that C++ uses to limit bloat do not apply well in a dynamic language) so they got stuck with the latter, for objects.

In Java, the code goes to add something to a generic list for example and it does one cast to the generic parameter type. Many times it can completely remove this check since it already knows from flow that the type is compatible. CLR can do this too, but only if it *also* knows the specific instance of the list (what the generic parameter types are), so it can remove fewer checks. This makes optimization harder as well since each use of a generic parameter can potentially block inlining and/or hoisting.

On top of that, the tests CLR has to do are *much* slower since they have to check many parallel type hierarchies (one per generic type references). For example, when passing a LinkedList of Integers to a parameter of type List of Numbers CLR has to in effect check both List assignable from LinkedList and Number assignable from Integer.

So in the vast majority of code not only do you end up with more checks but slower ones, and CLR has to maintain a complicated hierarchy of instantiated types to optimize this. All so primitives can be used faster in some cases, which is pretty ironic since in my experience these cases are usually easy to optimize by hand to use an array or patch out to inline C++ or JNI'd code.

In other words they messed up their runtime for bullet points without considering the implications. Not even to mention that in Java if you don't like generics, you just don't use them.

Too bad Java generics are completely useless

Amongst those changes (enumerations, auto-boxing, foreach, varargs) generics was the most far-reaching, introducing generic programming in a simpler, safer way than C++ templates and, unlike generics in C#, maintaining backwards (and forwards) compatibility with existing Java code.

Yeah, and by maintaining that backwards compatibility, they became totally worthless.

The only thing it offers is some compile-time sanity checking, but even that can be disabled through use of a new compiler pragma directive to suppress warnings. In fact, in several cases, you HAVE to disable warnings because certain operations (like creating an array of a generic type) are impossible without a warning.

Ever wondered why the collection classes require you to pass in an array to the toArray(T[]) method? Because Java generics throw away the class information after compile time (although there's no reason they need to do this, they could have kept it and maintained backwards compatibility), so you have to pass in an array to give the type information Java removed.

Java generics could have been useful, but since casting them into a non-generic type generates an ignorable warning, they become worthless. It's only a few lines of code to place a Double into an Integer collection, thereby removing then entire point completely.

Re:Too bad Java generics are completely useless

The only thing it offers is some compile-time sanity checking, but even that can be disabled through use of a new compiler pragma directive to suppress warnings.

Many operations are ERRORS, not warnings. This is caught by IDEs, and by the compiler.

In order to make it possible to interact with legacy code, you can pass a generified collection to a method that expects a "raw" collection. This gives you a very clear warning. So for 95% of all use cases, generics give you a lot of assistance. You manage to come up with a remaining 5% example, where a programmer casts, suppresses compiler warnings, and then passes in a object of the wrong type, and this makes generics worthless?

Wadler was involved with the design of Haskell, and he and people like Gilad Bracha designed Java generics. I trust their skills more than a Slashdot Anonymous Coward.

Reading Generified Code Makes My Brain Hurt

I don't use any of the generic syntax at all in my code as I feel it makes it virtually unreadable to other developers. The syntax is just absolutely horrible, plus as most adept Java programmers know (been coding in Java myself since 1.0), the way generics is implemented in Java is broken (depending on your point of view on this matter).

Then there is the Collections API itself which upon first glance seems like it was written by amateurs who have never had to write any performance critical code in their lives. For this reason as well, I generally try and avoid using anything in java.util as well.

And now they are talking about adding closures (more bloat) to Java which as I understand the proposal will be implemented under the hood in basically the same way as inner classes (another feature that is a maintenance nightmare that gets abused by novice developers ad infinitum).

Is Java not bloated enough? Do the guys at SUN have such feature envy of C# (the bastard child of Java), that they can't just say enough is enough?

I feel like this is all coming full circle with C++ in the sense that Java now has so many language features that it is becoming too complicated for entry-level developers to be truly productive with and now a new language is needed that has the best features of Java, minus all the bloat that totally overwhelms the initiates.

With more features, generally comes more power, but with more power there is more room for abuse for those who don't have the wisdom to use it (i.e. newbies). Everyone in programming starts off as a newbie and needs to get their feet wet, but once you make a programming language where everyone has a light saber, but does not have the Jedi training or wisdom to use it, well then you are going to have a lot of people causing a whole lot of trouble.

One of the main reasons why Windows software development has slowed to a crawl (besides of course the cannibalizing nature of MS on the Windows platform), is that it takes a good 4 years or more of full-time experience with the Windows API's just to become adept at programming on that platform, on top of being decent at C/C++ itself. I know Microsoft has tried to reduce that learning curve with C# and .NET, but nevertheless the learning curve is still huge. With Java, the same thing is happening. What was once a simple, yet powerful programming language has evolved into a monster on par with the same kind of crap that comes out of Redmond that is overengineered and the last thing from elegant.

I guess it is time for a new application programming language.

Re:Reading Generified Code Makes My Brain Hurt

Bullshit.

Generics syntax is quite readable and easy-to-use, especially with good IDE support. And generics certainly make the code more readable because the add type information.

Foreach loops, varargs and autoboxing is just a minor syntax sugar, nothing really big.

I've used a lot of collection frameworks in a lot of languages (and even wrote my very own vector and string for C++), Java Collections Framework is quite OK. It's not hard and reasonably fast.

Generics, jeez

The original post is being just a little specious on generics -- the reason Java generics are backwards compatible is that they aren't generics, they're just automatic type conversions when accessing collections. Whee. C# generics may not be up to the level of true generic programming (e.g. C++) but they are at least 'templates' in the sense that ArrayList is a different type from ArrayList.

Java has come a long way but there's still a reason Java programmers cost about 60% of the cost of actual C++ programmers (curse them).

Two words: Type erasure

Java generics are kept back-compatible with the old VM spec by way of type erasure: parametric information is "erased" from the type when it is compiled. So List and List and List all compile down to the same type: List.

Among other hiccups this makes it impossible to overload methods whose argument types differ only in the parametric information included with them.

By contrast, C++ templates and C# generics create a type disjoint from all other types in the same type class for each set of parameters in the type declaration.

Yet another sterling example of Java lossage.

Two words: Bracket erasure

Sentence in the above post should have read as follows:

So List<String> and List<java.math.BigInteger> and List<javax.swing.JComponent> all compile down to the same type: List.

Java-only programmers?

Wouldn't someone have to be used to _only_ Java to not be familiar with at least some of these concepts?

Enumerations are available in Pascal and pretty much all of its descendants IIRC. It's also a type of field in an SQL database for much the same purpose as enumerations in programming languages.

The foreach loop has been in Perl since 2.0 in 1988. C# got foreach in 2000. It's in PHP. It comes from earlier FOR..IN loops from shells.

I'm sure there are examples of the other features which are similar to the Java version of them. The syntax may be different, and the exact details of darker semantic corners may be different. The concepts, however, are pretty easy to have run across unless someone has only used the one language.

The review seems to imply that bringing in what has been proven to work well in other languages is too confusing and should be done at a slower pace. The truth is, people program in a subset of any general-purpose language at first, and that subset grows over time. If someone works with code from other programmers, one picks up the parts of the language to which they are exposed as they are exposed to them. No one needs to cram all night to be up on all the new features of a language the day after the manual gets updated.

warning: nitpicks ahead

introducing generic programming in a simpler, safer way than C++ templates and, unlike generics in C#, maintaining backwards (and forwards) compatibility with existing Java code."

*prepares to be modded troll*

People need to stop comparing Java/C# generics to C++ templates - they take similar syntax, but they aren't the same thing. I'm not sure how one can even be safer than the other.

And C# 2.0 maintained compatibility with existing C# 1.0 code (you still have access to the old containers) while actually giving significant performance benefits where Java is only syntax sugar that still produces the same old slow code.

Java One session

Naftalin and Wadler are also holding a Java One session this year, it is on Wednesday, session id is TS-2890. If you have a Sun Developer Connection account (free) you can watch it online after the conference is over.

I agree with reviewer, the book is very good. It is true that Java generics is a compile time check, and that the generics information is removed (erasure). Nevertheless, that was a deliberate tradeoff for backwards compatibility, and it still makes coding complex Java a lot safer and easier. Look for instance at the 1.5 and 1.6 improvements to the concurrency libraries [sun.com] with Future, Callable and Executors.

Not a good way to teach

OK, this finally is a comment about the book itself, and not about its subject. In my practice, it is almost impossible to get people to understand that generics do not mean "a List of Objects now becomes a List of objects of certain type". Once a person latches onto this notion (that parameterization is simply a way of indicating something similar to a collection), he is almost impossible to shift from it - I've tried explaining the declaration of the base Enum (which is Enum<E extends Enum<E>> - to get the compareTo () to work in a type-safe manner) to seasoned Java developers, only to get (without exception, or even a Throwable): "Oh, I get it, that means that Enum contains other Enum-like things!". And yet the book dives right into this concept; the first glimpse of the actual meaning of parameterization does not appear until the section 2 of chapter 3, a good one third way through. If I were to do it the right way, I'd start with <T extends Comparable<T>>, explain it thoroughly, and only then allow Collection to enter the picture. So, I would disagree with the reviewer - if you want to understand ? super Foo, this is not the book, unless you are willing to skip the first 2 chapters.

C++ Templates

While Java generics may be simpler and easier to use than C++ templates, they fall far short of the feature set of C++ templates. They do not really provide "generic programming" in the same sense that C++ templates do. There is much more to generic programming than being able to have a HashMap.

Poppycock

The most far reaching changes to Java in Java 5 are the changes to improve support for concurrency. Generics are just syntactic sugar that improve compile time type checking. The concurrency support features offer fundamental improvements in the way you can structure your applications to take advantage of increasingly parallel hardware architectures.

foreach

This is a great construct, but I found that it can be quite inefficent because it creates an Iterator and uses that to traverse whatever is being passed. For some collections such as ArrayLists, I found using a good old loop and .get(index) performed much faster and avoided creation of Iterators and therefore needed less garbage collection. Foreach is very neat and great in lots of places, but it should come with a small health warning for the cases where performance is critical.

My application was very heavy on traversing ArrayLists though.

Java 5 SCJP

I'm less than two weeks away from taking the Java 5 certification exam, and Generics are definitely the most difficult new concept for me to get my head wrapped around. Granted I haven't studied it nearly enough yet and haven't done any large scale projects in 1.5 (we use 1.4.2 at work), so hopefully I'll be well prepared by the time next Friday rolls around. I use the Sierra, Bates SCJP book to study and it supposedly has everything I need to know about Generics for the exam, but is it everything I need to know for the "real world"? Maybe I'll check this book out, but after the exam. Don't want to get confused with real applications of generics. :)

What they said

Java generics are mildly useful. To even mention them in the same breath as C++ templates, however, is extremely misleading. C++ templates go far beyond simply providing type-safe collections.
<soapbox>Of course, both mechanisms are work-arounds for the defects in the strongly-typed language paradigm. For the right way to handle types, look at python. Python uses untyped references to refer to typed objects, and written code is far simpler.</soapbox>

Sneaky compiler error?

If you see the error at compile time, then it's not sneaky. Feel free to use generics with Java 5. Just be sure that your work compiles ...

Compared to Duck Typing?

I have not done any Java in years. I wonder how this compares to duck typing as in Ruby. Can anyone explain this in terms of Ruby's duck typing and collections?

-matthew

Features or Fixes

Any features included to the language, after the first release, would hardly be called as features. They just are fixes for incomplete first release. Either language designers were not aware of these already existing features (obviously, this can not be true), or, they chose not to include those features to the language.

badly designed

unlike generics in C#, maintaining backwards (and forwards) compatibility with existing Java code

As a consequence of Java's attempts to maintain backwards compatibility, Java generics are nearly useless. They fail to make your code statically type-safe, and they fail to make it run faster. Yet, despite failing to achieve the two primary purposes that generics have, they still make the language considerably more complex. In contrast, using generics in C# does give you extra type safety and extra performance compared to casting.

Unedited Version

No really exciting differences, but the text without Slashdot's edits (which removed links, sub-headings and a paragraph that explained what I was doing) can be found here [acooke.org].

Re:Propz To Dead Homies yo!

It's hard to beleive you're posting at -1

Re:C# compatibility? duh...

I don't think there's any merit to that particular statement about backwards compatibility. Can you run you Java 5 code on a Java 2 VM? (They skipped 3, 4 and 5 right?) Generics were released with .Net 2.0. All the the .Net 1.1 code written runs on the 2.0 VM. There wasn't a whole mess of API changes that were obsoleted with the 2.0 it was ehancements to the API and bug fixes. What does forward compatibility even mean?

Re:C# compatibility? duh...

Uhm, can someone explain to me how NEW features of a language can be backwards compatible?

Can I create generics in Java 1.1? If not then how exactly is their generics implementation backwards compatible? Call me crazy but I'm a bit skeptical. I just don't see how this can be done in ANY language. Just because you can run multiple versions of the runtime on the same machine doesn't mean that your new code is backwards compatible.

Re:C# compatibility? duh...

Uhm, can someone explain to me how NEW features of a language can be backwards compatible?

Ummm... I think it means that programs that were written with previous versions of the language will not be broken by the new version and will continue to run correctly. That's what "backward compatible" has always meant, at least in my lifetime...

Re:C# compatibility? duh...

> If your code uses Java 5 features then it won't run on JDK1.4.

Your wrong. Or at least when it comes to Generics (I haven't tested the rest). Everything is done at the compiler level. So even if you use Generics the code is changed to work in 1.4 if you set javac -target 1.4.

Re:C# compatibility? duh...

The language feature of generics *is* new. The compiler can still compile Java 1.1 source and can even compile to older class file versions. The generics implementation is for compile-time type checking, not runtime type checking. The compiled class file has no knowledge of generics.

Re:C# compatibility? duh...

Man, that is just not fair. Microsoft has been burdened with backwards compatibility like no other company out there. I mean, except on 64-bit Vista, you can still run 16-bit DOS apps in the latest release of Windows, 20+ years later! Try running a circa 2001 OS9 app on a new Mac, and let me know how that goes for you. Microsoft has been hamstrung by their commitment to backwards compatibility; I am convinced that (and bad management) are the reasons for Vista's mediocrity. Yeah, some stuff broke, but I wish they'd broken more in the pursuit of a "good" OS.

On topic, C# 2.0 was introduced with .NET 2.0, which included bytecode optimizations that aren't backwards-compatible. The generics stuff probably could have been, but meh; Microsoft controls the only real .NET platform anyhow. Its not like they had to remain compatible with mobile phones and such, like Sun did.

Re:All Roads Lead to Rome

Unworkable. Polymorphism and ifs/switches are SEVERAL ORDERS OF MAGNITUDE faster than database access. So it's better to keep them separated.

As for metaprogramming - you can look at Nemerle (http://nemerle.org/Main_Page) which excels at metaprogramming. It's one of the best languages I've seen.

But there's research in bridging the gap between databases and code - see http://en.wikipedia.org/wiki/Language_Integrated_Q uery [wikipedia.org] for an example.

Re:C# compatibility? duh...

Who ever saw a version of a Microsoft product that was compatible with the previous version?

Are you joking? I hope you're joking. Because the alternative is that you are being criminally thick. I really think Slashdot should have a mod option -1 Misinformed

Say what you will about Microsoft, but backwards compatibility has always been one of their cornerstones. Their compatiblity layers still allow you to run apps from the early 90's on a modern copy of Vista today. I have managed to get some very old VB3 code working with a minimum of modification on VB6, which then, using Project Analyzer, got compiling in .NET in a matter of (admittedly frustrating) days.

And who are you comparing them with? Linux? You must be joking. Linux has trouble (read: is completely unable to) maintain binary compatibility with even relatively recent "old" code because of changing libc versions, etc.

Please, name ONE other operating system out there that can claim to run decade-old binaries flawlessly in its most recent incarnation.

Disclaimer: I'm a dedicated FOSS user and not a Microsoft shill in any way. But please, let's give credit where credit is due.

Re:C# compatibility? duh...

Utter BS. I worked for a couple of years developing Win32 apps. We supported everything from 95 through to XP and I can assure you that there is NO FUCKING WAY that the OS runs the old binaries flawlessly!

The code is riddled with conditional paths for different OS versions. Testing across windows versions was a nightmare.

I suggest it's you who is being criminally thick.

And modded up, too

That's clever, yes. I suppose there has to be one of these in every "discussion". Thanks for increasing the signal-to-noise ratio and all that.

Re:Sticking to Java 1.4.2.x

I agree mostly, though varargs I have found to actually be very useful in a few cases where it can greatly improve readability. (though due to the reflection aspect of how varargs works under the hood, they should never be used in performance critical code). As for everything else, well yah it is just syntactic sugar.

Unfortunately, lazy or newbie programmers will use autoboxing and varargs more than just sparingly and being the second generation coder on a project where these features are used liberally is a hell I would not wish on my worst enemy.

Re:Sticking to Java 1.4.2.x

Sorry, but that means you don't want to learn new things.

Generic code is much easier to maintain and read because you have MORE type information. Another changes like foreach loop and varargs are just syntax sugar and do not deserve more than a few minutes of attention.

Re:Sticking to Java 1.4.2.x

I would love to see Java drop inheritance off entirely (and I have used it correctly too,) but there is no need for it really. Everything can be done with interfaces and libraries.

You know, one of the biggest critisisms of classic VB was always that it only had interfaces and libraries, and not real implementation inheritance.

I think what I'd like to see if for polymorphism to be done entirely with interfaces, and for implementation inheritance to be supported, but hidden from client code.

Re:Sticking to Java 1.4.2.x

At this point I believe that the fewer language features and sugars allowed by the compiler outweighs the performance benefits of the newer JVM. I wouldn't let a new project start on anything above JVM designed for 1.4

Re:Sticking to Java 1.4.2.x

Well, I don't control the mods, but the intent of my previous post (the parent post) was most definitely not to troll anyone. Any intelligent person would see that.