[RyanZAG]

Java is very heavily set on backwards compatibility - no new feature is allowed to affect existing code and any new features must fit into the existing features. This is different to Python for example where they had backwards incompatible changes in v3.

Another issue is the depth of the process on each change: there are a number of discussions on each feature with multiple proposals to determine the best way to implement any feature and how it will fit in, etc. The number of companies and people involved in the feature design and implementation in each change is generally an order of magnitude greater than those other languages.

Comes down to heavy bureaucracy and design by committee creating a very long process - but the end result is generally extremely well thought through and tested, so I'm personally not complaining since I'm not footing the bill.

[pron]

I think that while backwards compatibility has always been a very important concern of Java's (as it should for such a popular language), this is also a matter of philosophy. Java's maintainers know that every feature comes at a price (of complicating the language), so the first consideration is always whether the feature provides enough benefit to justify its cost. The second consideration is whether the feature conforms with Java's "spirit" as a "blue-collar" language, designed for use on multi-MLOC projects, possibly worked on by hundreds of developers. Such a language has different requirements and a different "feel" from languages designed for quick development and comparatively small teams.

Obviously, at this stage Java has accumulated quite a lot of baggage, as could be expected from such a mature and ubiquitous language. Some of these issues are addressed in Java 8, and some by other JVM languages with various degrees of adherence to the Java philosophy.

I would strongly recommend watching these two talks by Joshua Bloch, where he explains Java's goals, philosophy and design. These goals were later adopted by Google for their own new languages, Dart and Go, that have the same "Java feel":

* http://parleys.com/play/514892250364bc17fc56bb15/chapter11/a...

* http://parleys.com/play/514892290364bc17fc56c444/chapter0/ab...

[frowaway001]

> but the end result is generally extremely well thought through and tested

Have you looked at the API of function types? If we needed a definition of incoherent, overcomplicated, painfully stupid non-sense, this would be it.

I'd say the issue with Oracle's style of development is that it is primarily time-driven which just doesn't work for evolving languages.

Features are not developed and shipped when they are ready. Instead, they decide that they want to ship X in the upcoming version Y and sacrifice the quality to reach the dead-line.

Of course, stuff is ugly and inconsistent if it has been rushed all the time.

That the persons involved in designing those features are completely under-qualified doesn't help either.

[RyanZAG]

Only briefly - it looks pretty straight forward. Could you explain what's wrong with it?

Also they pushed a number of features that were going to land in Java 7 back to Java 8 because there wasn't enough time to finish them. So that doesn't seem to be true.

[frowaway001]

> Only briefly - it looks pretty straight forward. Could you explain what's wrong with it?

I think this link says it all: http://download.java.net/jdk8/docs/api/java/util/function/pa...

The amount of times they managed to back themselves into a corner is just horrifying.

> Also they pushed a number of features that were going to land in Java 7 back to Java 8 because there wasn't enough time to finish them. So that doesn't seem to be true.

And to Java 9. Any actual improvement would assume that a considerable amount of people would have kept working on those things in the meantime. First delaying the feature and then reallocating the people to extinguish fires somewhere else (security, applets, ...) doesn't help.

Anyway, they recently started from scratch again on modularization, so pretty much all the work done on Jigsaw before that is lost anyway. Let's at least hope that they documented the experience they gained, so that they don't repeat all the mistakes again.

[pron]

> I think this link says it all: http://download.java.net/jdk8/docs/api/java/util/function/pa....

I'm not sure you understand what you're looking at. Defining a "function type" in Java 8 looks like this:

  interface MyFunctionType {
    double f(String x, Runnable y, int z);
  }

That package merely defines some common types. They are all interchangeable, by the way, so if your method takes a parameter of type "YourFunctionType", defined so:

  interface MyFunctionType {
    double foo(String a, Runnable b, int c);
  }

Then the same lambda expression could represent both MyFunctionType and YourFunctionType. You don't need to use the types defined in that package, you don't need to remember what they're called etc.

> Anyway, they recently started from scratch again on modularization, so pretty much all the work done on Jigsaw before that is lost anyway.

I'm not sure how much is "lost", but most Java users specifically said, in this case and in others, that they prefer postponing a feature until its been done "right" after die consideration. And when a language is used by millions of developers and with trillions lines of existing code, there is a lot to consider, because a lot is at stake.

[frowaway001]

> I'm not sure you understand what you're looking at.

Yes, I do. The issue is that their ideas of lambdas work exactly in those cases where using a lambda is just a nice replacement for existing AICs. With that reasoning they thought that they could get away without standard function types.

But then, they added their "bulk operations" to collections and started to realize they were in trouble, because there didn't exist any SAM types they could use _and_ coming up with names for anonymous function literals was kind of idiotic. But with function types already ruled out and time running short, they decided to make up ad-hoc function types.

A bit later, they also realized that all the boxing had a non-negligible impact on performance, so they started to add _some_ ad-hoc specializations to the already ad-hoc function types, but of course not _all_ of them. Not even mentioning that the naming is just completely out of whack.

At the same time, they started to ask people what use-cases they could think of for real Generics in Java 9. One could argue that it's a case of the left hand not knowing what the right hand does at Oracle ... but it was in fact the _same_ person who OK'ed the broken function type design in the first place who was now asking for feedback.

So in the best case, a considerable amount of types in java.util.function (did I already mention that the name is just FUBAR?) will be obsolete in the version right after Java 8 and in the worst case, those types will serve as ammunition against fixing Generics for good.

This is a good case of making every imaginable error in language design one can think of.

> most Java users specifically said, in this case and in others, that they prefer postponing a feature until its been done "right" after die consideration

Yeah. I think no one will ever argue against that. You are not making up straw men again, aren't you?

What people criticize is that what Oracle claims is not consistent with their actions. If you want to sell people the idea of delaying a feature to "get it right", for gods sake, please actually make sure you "got it right" when shipping it versions later.

[pron]

> But then, they added their "bulk operations" to collections and started to realize they were in trouble, because there didn't exist any SAM types they could use _and_ coming up with names for anonymous function literals was kind of idiotic. But with function types already ruled out and time running short, they decided to make up ad-hoc function types.

This is simply not true. Doug Lea, the author of java.util.concurrent, and of ForkJoin in particular, was one of the main driving forces behind lambdas; he requested them about 7 years ago precisely for those bulk operations. The same Doug Lea rejected function types way back then in favor of CICE.

Already back in 2007-2008 it became clear that function types are a bad fit for Java. Java's designers explicitly mentioned currying, general functional-style programming, and user-defined control structures as things they wanted to avoid. These things may very well have a place in other programming languages, but not in Java. If you don't want a blue-collar programming language then Java is simply not meant for you. Java, like Clojure or Haskell, has a very specific flavor. A feature can be right for one language but not for another.

> A bit later, they also realized that all the boxing had a non-negligible impact on performance, so they started to add _some_ ad-hoc specializations to the already ad-hoc function types, but of course not _all_ of them. Not even mentioning that the naming is just completely out of whack.

Again, not true. Java's designers are extremely focused on performance, and did not "realize" all of a sudden boxing has a non-negligible impact on performance. Also, those are not "ad hoc" specializations. All they did was pre-define some small subset of possible function types that they figured will be widely used. Again, the idea is always do the least "powerful" thing possible that will give you the most benefit.

[laureny]

> Anyway, they recently started from scratch again on modularization, so pretty much all the work done on Jigsaw before that is lost anyway

Nonsense. Just because you throw out a design doesn't mean that "everything is lost": you've learned a lot in the process and you're going to use that knowledge to draft the next design.

Java is often made fun of for moving at a glacial pace but quite a few languages could learn a thing or two about the benefits of shipping features that are designed right from v1 (Scala has been much more reckless in that area).

[frowaway001]

> Nonsense. [blabla]

... which is exactly what I said in the next sentence, right? :-)

> but quite a few languages could learn a thing or two about the benefits of shipping features that are designed right from v1

Eh, could you mention a few things which were "designed right from v1"? I can only imagine enums, but what else?

[pron]

This is a talk by Brian Goetz about the design of Java 8's lambdas: http://parleys.com/play/5251c164e4b0a43ac1212459/about

A lot of thought has been put into that, and I think the result is both elegant and at the same time integrates beautifully with legacy code. Perhaps most importantly, a lot of existing libraries will automatically support lambdas naturally without them ever being designed for lambdas and without recompilation.

Java's lambdas have been anything but rushed. They were debated long and hard (for literally years), and different approaches were considered, tried and discarded before the present spec was accepted. Here's a summary of the discussion from 2007: http://blog.joda.org/2007/12/closures-comparing-core-of-bgga...

In the end, the "BGGA" proposal for full function types in Java was rejected in favor of something similar to the Doug Lea-Josh Bloch-Bob Lee proposal. Bob Lee summarized his perspective so[1]: "Loosely speaking, simple syntax sugar for anonymous inner classes buys Java 90% of the power of BGGA closures while carrying only 10% of the weight. We think it's the "knee in curve" where we get the most bang for our buck." This is perfectly in line with the Java philosophy. Other languages may prefer getting 100% of the power for ten times the cost, which might make sense if your requirements and use cases are different.

In the end, though, Lambda's are more powerful than the original "concise syntax for anonymous classes" because method handles are used as the bytecode-level description of lambdas, while anonymous classes are an implementation detail that can be changed later without affecting binary compatibility.

This talk by Joshua Bloch, discusses "the closures controversy" in some depth: http://parleys.com/play/514892250364bc17fc56bb15/chapter0/ab.... He explains that PL research was a declared "non-goal" for Java, which was meant to be kept simple. "Nice" features were rejected by design, with the goal of only including those that solve problems that really hurt.

P.S.

The lambda discussions predate the Oracle acquisition. Also, I wouldn't call Gilad Bracha, Joshua Bloch and Guy Steele underqualifed.

[1]: http://blog.crazybob.org/2006/10/java-closure-spectrum.html