One Year After Java 8’s Release, IDEs and Compilers are not Fully Ready Yet

One year ago, on March 18, 2014, Java SE 8 was released, and with it, the bliss of functional programming through lambda expressions and the streams API. These were great news for all of our Java ecosystem, and many people have already upgraded to Java 8. Stack Overflow already yields almost 2500 questions about Java 8 (with Brian Goetz himself answering). Also, Google Trends shows a massive increase in search volume


But even after one year, neither the javac compiler, nor the three major IDE compilers are fully Java 8 ready yet. This question by user meriton was asked on Stack Overflow, recently:

Lambda type inference infers an exception type not thrown by the lambda

The question shows the following piece of code:

class TestException extends Exception {

interface Task<E extends Exception> {
    void call() throws E;

public class TaskPerformer {

    private <E extends Exception> void perform(Task<E> task) throws E {;

    public static void main(String[] args) {
        // compilation error
        new TaskPerformer().perform(() -> {
            try {
                throw new TestException();
            } catch (TestException e) {

The false positive compilation error has probably been fixed with issue 429430. In any case, it is not reproducible with Eclipse 4.5.0 M5, available as a developer build

With Java 8, compiling Java code hasn’t really become any easier than before. The above bug has been produced by a very subtle combination of:

  • Checked vs. unchecked exceptions
  • Generics (and exceptions)
  • Lambda expressions
  • Type inference
  • Flow analysis

If you’ve ever had a look at compiler source code, you cannot help but be glad that someone else is doing that job for you (the same is true when you look at jOOQ’s or Hibernate’s sources, by the way).

Where are we at with our compilers?

We’re getting there. My personal feeling is that early access releases of javac work best. For instance, I’m using

build 1.8.0_40-ea-b23

(disclaimer: this article was written before it was published. many problems are now gone with 1.8.0_40)

… although, you probably don’t want to go to production with such an early access release. IDEs building with javac, and Maven, of course, work equally well. Eclipse is lagging a little bit – which can be annoying at times.

Some of you non-Eclipse users might smirk and get your Eclipse vs. IntelliJ rants ready, and you know… there’s a saying about that:

A vegan, an IntelliJ user, a Mac user, and a Linux user walked into a bar.

How do I know?


(We actually have a whole article on that topic)

The fact is, all of the compiler teams are working hard to fix loads of bugs. IntelliJ, even while using javac to compile, may still display some false positives, visually in your IDE. Geertjan from NetBeans has just recently fixed a whole pile of bugs that we’ve reported. And Eclipse, well, Eclipse ships with their own very sophisticated incremental Java compiler. It’s a great compiler for rapid prototyping, but the drawback is that it compiles stuff slightly differently from others.

While developing jOOQ and also jOOλ, we’ve discovered quite a few bugs in Eclipse – many of them having been fixed already in Eclipse Mars. For instance:

We’re getting there. If you can, make use of lambdas and streams, and apply as much type inference in your code as possible. And please, if you do discover a bug, report it. We’re probably all using one of those three IDEs. Every bug that you report, is one less obstacle towards Java 8 adoption.

Here are the links to start registering bugs:

Top 10 Very Very VERY Important Topics to Discuss

Some things are just very very very VERY very important. Such as John Cleese.

The same is true for Whitespace:

Yes. 1080 Reddit Karma points (so urgently needed!) in only 23 hours. That’s several orders of magnitudes better than any of our – what we wrongfully thought to be – very deep and interesting technical insight about Java and SQL has ever produced.

The topic of interest was a humourous treatise about whether this:

for (int i=0; i<LENGTH; i++)

… or this:

for (int i = 0; i < LENGTH; i++)

… should be preferred. Obviously both options are completely wrong. The right answer is:

(   int i = 0
;   i < LENGTH
;   i++

Read the full treatise here.

But at some point, the whitespace discussion is getting stale. We need new very very very important topics to discuss instead of fixing them bugs. After all, the weekend is imminent, and we don’t know what else to talk about.

This is why we are now publishing…

Top 10 Very Very VERY Important Topics to Discuss

Here we go…

0. Whitespace

OK, that was a no-brainer. We’ve already had that. Want to participate? The very interesting Reddit discussion is still hot.

1. The Vietnam of Computer Science

In case you haven’t heard of this highly interesting discussion, there are some people who believe that ORMs are outdated, because ORMs don’t work as promised. And they’re totally right. And the best thing is, all the others are totally right as well.

Why is that great? Because that means we get to discuss it. Endlessly!

While everyone keeps talking about ORMs like that, no one cares what Gavin King (creator of Hibernate) had said from the beginning:

Why should we care about his opinion? We have our own, far superior opinion! Let’s have another discussion about why ORMs are evil!

2. Case-sensitivity

Unfortunately, us Java folks cannot have any of those very very very very very important discussions about casing, because unfortunately, Java is a case-sensitive language.

But take SQL (or PL/SQL, T-SQL for that sake). When writing SQL, we can have awesome discussions about whether we should

-- Upper case it all

-- Upper case keywords, lower case identifiers
SELECT tab.col1, tab.col2 FROM tab

-- Lower case keywords, upper case identifiers
select TAB.COL1, TAB.COL2 from TAB

-- Lower case it all
select tab.col1, tab.col2 from tab

-- Add some PascalCase (awesome SQL Server!)
SELECT Tab.Col1, Tab.Col2 FROM Tab

-- Mix case-sensitivity with case-insensitivity
-- (Protip to piss off your coworkers: Name your
-- table "FROM" or "INTO" and let them figure out
-- how to query that table)

-- PascalCase keywords (wow, MS Access)
Select TAB.COL1, TAB.COL2 From TAB

Now that is really incredibly interesting. And because this is so interesting and important, you can only imagine the number of interesting discussions we’ve had on the jOOQ User Group, for instance, about how to best generate meta data from the database. With jOOQ, we promise that you can extend these enticing discussions from the SQL area to the Java area by overriding the code generator’s default behaviour:

  • Should classes be PascalCased and literals be UPPER_CASED?
  • Should everything be PascalCased and camelCased as in Java?
  • Should everything be generated as named in the database?

Endless interesting discussions!

jOOQ: The Best Way to Write SQL in Java

We have so many options to SQL casing, which brings us to

3. SQL formatting

Unlike C-style general-purpose languages such as C, Java, Scala, C#, or even keyword-heavy ones Delphi, Pascal, Ada, SQL has one more awesome grounds for numerous discussions. It is not only keyword-heavy, but it also has a very complex and highly irregular syntax. So we’re lucky enough to get to choose (after long discussions and settlements) between:

-- All on one line. Don't tell me about print margins,
-- Or I'll telefax you my SQL!
SELECT table1.col1, table1.col2 FROM table1 JOIN table2 ON = WHERE id IN (SELECT x FROM other_table)

-- "Main" keywords on new line
SELECT table1.col1, table1.col2 
FROM table1 JOIN table2 ON = 
WHERE id IN (SELECT x FROM other_table)

-- (almost) all keywords on new line
SELECT table1.col1, table1.col2 
FROM table1 
JOIN table2 
ON = 
WHERE id IN (SELECT x FROM other_table)

-- "Main" keywords on new line, others indented
SELECT table1.col1, table1.col2 
FROM table1 
  JOIN table2 
  ON = 
  FROM other_table

-- "Main" keywords on new line, others heavily indented
SELECT table1.col1, table1.col2 
FROM table1 JOIN table2 
              ON = 
             FROM other_table)

-- Doge formatting
SUCH table1.col1,
    MUCH table1
JOIN table2 WOW
WHICH              id IN
   (SUCH x

WOW other_table
Doge SQL Formatting

Doge SQL Formatting

And so on and so forth. Now any project manager should reserve at least 10 man-weeks in every project to agree on rules about SQL formatting.

4. The end of the DBA

Now THAT is a very interesting topic that is not only interesting for developers who are so knowledgeable about productive systems, no it’s also very interesting for operations teams. Because as we all know, the DBA is dead (again).

For those of you who have been missing out on this highly interesting topic, do know that all of this started (again) when the great NoSQL vs. SQL debate was initiated by brilliant minds and vendors of truly alternative systems. Which are now starting to implement SQL, because apparently, well… SQL isn’t all that bad:

Please, do engage in some more discussions about the best and only true way to tackle database problems. Because your opinion counts!

5. New lines and comments

Remember our own blog post about putting some keywords on new lines? Yes, we prefer:

// If this
if (something) {

// Else something else
else {

Exactly. Because this allows comments to be written where they belong: Next to the appropriate keyword, and always aligned at the same column. This leads us to the next very interesting question: Should we put comments in code at all? Or is clean code self-documenting?

And we say, why yes, of course we should comment. How on earth will anyone ever remember the rationale behind something like this??

// [#2744] DB2 knows the SELECT .. FROM FINAL 
// TABLE (INSERT ..) syntax
case DB2:

// Firebird and Postgres can execute the INSERT 
// .. RETURNING clause like a select clause. JDBC
// support is not implemented in the Postgres JDBC
// driver
case POSTGRES: {
    try {
        rs = ctx.statement().executeQuery();
    finally {
        consumeWarnings(ctx, listener);


Taken from our “hacking JDBC” page.

6. JSON is totally better than XML

Of course it is! Because… because… errr. Because it allows me to structure data hierarchically. Waaaait a second…


You’re saying, JSON and XML are the SAME THING!?

But MongoDB and PostgreSQL allow me to store JSON. Oh wait. They tried to store XML in databases, back in the 90s, too!? And it failed? Well, of course it failed, because XML sucks, right? (which is essentially another way of saying that I’ve never understood XSLT or XQuery or XPath or didn’t even hear about XProc, and I’m just ranting about angle brackets and namespaces)

Let’s further discuss this matter. I feel that we’re close to the very ultimate solution on that topic.

Speaking of JSON…

7. Curly braces

OMG! This is the most interesting of all topics. Should we put the opening brace:

  • On the same line?
  • On a NEW line??

The right answers are 1) and 3). 1) only if we absolutely have to, as in try or switch statements. We’re not paid by the number of lines of code, so we don’t add meaningless lines with only opening braces. And if we can omit the braces entirely, fine. Here’s an awesome statement, if you ask me:

if (something)
    for (String thing : list)
            if (somethingElse)
                break inner;
                continue outer;
        while (true);

That ought to teach them juniors not to touch my code. Which brings us to:

8. Labels

Nothing wrong with them. I’ll break out of my loops any time I want. Don’t tell me labels are Java’s way of saying GOTO, they’re much more sophisticated than that. (Besides, goto is a reserved word in Java, and it is an actual bytecode instruction). So I’ll happily do my jumping forward:

label: {
  // do stuff
  if (check) break label;
  // do more stuff

Or my jumping backward:

label: do {
  // do stuff
  if (check) continue label;
  // do more stuff
  break label;
} while(true);

(observe how the above example used two spaces for indentation instead of four (or tabs). Another great topic for further discussion)

9. emacs vs. vim vs. vi vs. Eclipse vs. IntelliJ vs. Netbeans

Can we please, PLEASE, have another very interesting discussion about which one of these is better? Please!

10. Last but not Least: Is Haskell better than [your language]?

According to TIOBE, Haskell ranks 38.

And as we all know, the actual market share (absolutely none in the case of Haskell) of any programming language is inversely proportional to the amount of time spent on reddit discussing the importance of said language, and how said language is totally superior to the one ranking 1-2 above on TIOBE, for instance. Which would be Lua.

So, I would love to invite you to join our blogging friends below to a very very interesting discussion about…

Now, of course, we could enlargen the debate and compare functional programming with OO programming in general before delving into why Scala is NOT a functional programming language, let alone Java 8.

Oh, and you think your dialect of Haskell or Lisp is not good enough, so you should roll your own? Go ahead (right after checking this checklist!)

Such great topics. So little time.


The great thing about these social networks like Reddit, Hackernews, and all the others is the fact that we can finally spend all day to discuss really really intersting topics instead of fixing them boring bugs our boss wants us to fix. After all, this is IMPORTANT.

Or as Randall Munroe would say: “Duty calls!”

Further reading

If you’re now all hot and ready to discuss things, please consider also reading these very interesting and insightful articles on how to best format and style code:

Or add your own. There’s still much much important writing to do!

Top 5 Useful Hidden Eclipse Features

Eclipse is a beast. A device whose mystery is only exceeded by its power. Some would call it a continuum transfunctioner. Others would call it a transmogrifier. Yes, it is so huge, it takes years to master. And then, your manager shows up and tells you: We’re using NetBeans now.

Just kidding. No one uses NetBeans, except for Adam Bien. So let’s have a look at 5 very useful, but hidden Eclipse features.

1: My favourite feature: Favourites

Everyone uses libraries with static methods. Since Java 5, we can static import them, so we no longer have to write things like

SomeVeryImportantUtility.split(string1, string2);

But who is going to static-import all those methods manually in every class referencing them? No one. Because you can define your favourite types and members in the preferences:

Preferences > Favorites

Preferences > Favorites

And then, just start typing and look for auto-completion:



The auto-completion will also generate the necessary static import. Very useful when using DSLs with many functions, for instance. Obviously, you will want to make a careful decision, which ones are really your favourite libraries and within those libraries, which are your favourite types. As you’re on the jOOQ blog (or a syndication thereof), let me give you a hint. Always favourite org.jooq.impl.DSL.

2: The awesome block selection mode

I’ve recently blogged about it here. This is so awesome, it merits being mentioned one more time.

Block selection

Notice the highlighted button, the sixth from the left. That’s the awesome “Block Selection Mode” (Alt-Shift-A on Windows, or Ctrl+3 and then typing block selection). It lets you write opening quotes on each selected line at the same position. This is so useful when you have to edit large amounts of almost identical lines.

3: The EGit staging view

Aparently, not every EGit user is aware of this view. As a matter of fact, to me, this view is the most important reason why I’m NOT using the shell commands. Check out this beauty:

Staging view

Staging view

OK, not really a beauty. Reminds me of this comic strip by Eric Burke. But we’re in transmogrifier land and the staging view is filled with changes waiting to be added / committed / pushed once you synchronize a repository with its origin. I can now decide on a line-per-line basis, which changes I want to be added to the index (note I haven’t added the main method). This leads to there being staged (added) changes and unstaged (not yet added) changes. As always in EGit, I can now either directly commit, commit+push, amend+commit, amend+commit+push in one go. Try doing that on the command line.

Now after this first commit, I can now again stage/add the main method in a separate commit. I guess, behind the scenes, this might be implemented using stashing or some other sort of local cache. I don’t care, this is beautiful!

I can probably do much more with this beauty, but that would fill an entire book (I’m waiting for such a book, @niborst, if you’re reading this)

If you didn’t understand any of the above Git talk, try this popular guide, or join me with…

4: Type filters

Yes, because Eclipse’s out-of-the-box autocompletion is nonsense. Yes, it is! No one really wants to call hashCode() or wait() or notifyAll() on an API. Ever. Actually, nowadays, hardly anyone even wants to call wait() or notify() even on a lock object, except if they’re writing the JDK’s concurrency libraries. But luckily someone else is doing that for free, and they’re certainly using vi or emacs or a hex editor, so they don’t mind Object methods.

So then, why is my autocompletion popup filled with this nonsense? Let’s create a class…

So many options? Really?

So many options? Really?

Wow. I thought I had only one method? I don’t mind equals(), although the few times I actually type equals() I can type it out. So let’s remove that stuff:

Preferences > Type filters

Preferences > Type filters

Thanks Eclipse for mentioning awt, too. I wish there was an option to remove awt from the JDK and from our collective memory, entirely. But at least, adding awt to the type filters stops you from having to choose between importing java.util.List (99.9%) and java.awt.List (8.3%). The rounding error is due to the amount of times you had previously chosen the wrong list, accidentally, and wondered why you couldn’t assign an ArrayList. Thanks again, awt. Do also note how my chameleon Windows 8 has changed window colours while taking screenshots. Tiles, what’s next? Anyway back to Eclipse, let’s try auto-completing again…

There can be only one

There can be only one

Better? Better!


5: Formatter tags

After having spent all that time with block selection, carefully formatting our SQL… bam comes the intern and/or styleguide-nazi and auto-formats all your beautiful source files to a huge one-liner. But not for much longer. Protect your code with easy to type formatter tags:

Preferences > Formatting Options > Off/On Tags

Preferences > Formatting Options > Off/On Tags

Remember to use something concise to protect your carefully crafted SQL, as you might have to type these tags once or twice:

Now protected

Now protected

No one touches that code again. Except the intern who forgot to and/or styleguide-nazi who refuses to apply your formatting settings. And the other intern, who uses NetBeans. Just kidding. No one uses NetBeans.

Again, these tags work wonderfully with DSLs, which are hard to auto-format.

More to come

Eclipes is an awesome beast. Every year, new versions are stacked with new features that we Java developers get for free! You can give back to Eclipse. While I think that the foundation (backed by IBM) might not heavily rely on donations, your best option is to report bugs and feature requests, here:

… or if you’re brave, to sign the CLA and start contributing.

There is always room for improvement to this awesome developer device, adding more material and candidates for my next top 5 list.