Private APIs not usable in Java 9?

Stefan Fuchs snfuchs at
Wed Apr 8 21:03:20 UTC 2015


and one more thing, I don't care about Unsafe. It can die unless it is 
involved in a workaround for the StringIndexOutOfBoundsException in 
CertUtils.checkWildcardDomain we currently see in java 8u60-ea when 
opening an https connection to our servers. Hopefully this can be fixed 
till the final release.

But in all artificial restrictions to implement your own workarounds 
using private apis its another minus on our assessment of the risks 
involved, when investing in the javafx technology. Others are the 
diminishing plugin support by browser vendors and a lack of commitment 
from oracle for growing platforms like android or ios.
On the other side of the equation is unrestricted access of the 
application to the local filesystem and cpu resources and the rich java 

Currently the equation still holds in favor of javafx, but is constantly 

And as you can see at we currently use different 
technologies for the online editors of our print products. Still adobe 
flash for the simple products (Print products and Textile products) and 
an new JavaFX based editor in the same design as the flash editor for 
the more complex photo products. So an html5 editor could certainly 
become the successor of the javafx editor.

Anyway I think especially for webstart applications, which have no 
control over the installed jre should have the possibility to access 
private apis. If a installed application can do it, why shouldn't the 
same be possible for a webstart application?

<evil grin>
Or perhaps, as it has full access to the filesystem, my application 
could start patching class files in the installed jre....
</evil grin>

No, I don't think that would be a good idea.

- Stefan

> Hi,
> you are right, there are still years to the end of public updates to 
> JDK 8....   We can use them to migrate to other technologies.
> - Stefan
>> Making any theoretical flag available to the deployment side would 
>> entirely miss the point.
>> Let me be blunt -- sun.misc.Unsafe must die in a fire.  It is -- wait 
>> for it -- Unsafe.  It must go.  Ignore any kind of theoretical rope 
>> and start the path to righteousness _*/now/*_. It is still years 
>> until the end of public updates to JDK 8, so we have /*years */to 
>> work this out properly.  But sticking our heads in the collective 
>> sands and hoping for trivial work arounds to Unsafe is not going to 
>> work.  If you're using Unsafe, this is the year to explain where the 
>> API is broken and get it straight....
>> Please help us kill Unsafe, kill Unsafe dead, kill Unsafe right, and 
>> do so as quickly as possible to the ultimate benefit of everyone.
>>  - Don
>> On 08/04/2015 2:56 PM, Stefan Fuchs wrote:
>>> Hi,
>>> then I can only hope, that this flag is available to webstart 
>>> applications.
>>> Webstart applications have no control over the installed jre. In the 
>>> past we encountered various bugs in the jre, which required using 
>>> internal apis for workarounds.
>>> For example in some releases of Java 7 the swing gui thread did not 
>>> start unless hacking internal apis (see 
>>> for details). If such 
>>> an error occurs again in the future and we are no longer able to 
>>> hack around the problem, our only choice to keep our business alive, 
>>> is to discourage users from upgrading to newer versions of the jre, 
>>> exposing them to security risks.
>>> - Stefan
>>>> >  it's not strictly JFX-only.
>>>> Its not remotely FX only, in fact I could argue FX is not so affected,
>>>> as being relatively new it does not have 20 years of accumulation
>>>> of people using internal APIs that the larger JDK does, often 
>>>> dating from
>>>> when there were no suitable public APIs. There still remains some
>>>> of that with sun.misc.Unsafe as pointed out which will indeed be
>>>> inaccessible in modular mode. But the FX list isn't really the place
>>>> for that discussion. The jigsaw-dev is the appropriate list. FX
>>>> is simply bound by the rules that are set there.
>>>> There will be a -XX flag in JDK 9 that jigsaw provides to aid in 
>>>> the transition.
>>>> Also remember FX is open source. You can propose patches !
>>>> If there are specific APIs that are missing from FX that are suitable
>>>> to be *supported* public APIs then those could be considered here 
>>>> (this list).
>>>> -phil.
>>>> On 4/8/2015 9:28 AM, Mike Hearn wrote:
>>>>> sed -i 's/private/public/g' ;)
>>>>> The whole notion of a strongly enforced private keyword is IMHO 
>>>>> dumb when
>>>>> not using sandboxing. The number of gross hacks that occur in an 
>>>>> attempt to
>>>>> work around overly strict enforcement of this stuff is crazy. The D
>>>>> compiler has a special flag that disables visibility enforcement when
>>>>> compiling unit tests, and that's a good idea, but why not go all 
>>>>> the way
>>>>> and just make accessing of private state a compiler warning a la 
>>>>> deprecated?
>>>>> I also need to use private JFX APIs. I think any real JFX app 
>>>>> does, way too
>>>>> much basic stuff relies on it. Heck, the number of popular Java 
>>>>> libraries
>>>>> that depend on sun.misc.Unsafe is huge. If Java 9 stabs us in the 
>>>>> back in
>>>>> this regard then I will just write a simple tool that flips 
>>>>> private->public
>>>>> either at the source level or via bytecode editing, and see what 
>>>>> happens :-)
>>>>> On Wed, Apr 8, 2015 at 6:14 PM, Robert Krüger 
>>>>> <krueger at> wrote:
>>>>>> Hi,
>>>>>> I hope this is not too off-topic, because although it came up in 
>>>>>> a JFX
>>>>>> context it's not strictly JFX-only.
>>>>>> Someone from our team recently had a chat with a high-ranking 
>>>>>> regional
>>>>>> Oracle representative who gave a talk on the state of JFX. Our guy
>>>>>> explained our situation (evaluating JFX to migrate our 
>>>>>> swing-based product,
>>>>>> feeling it's in principle the right technology but still having
>>>>>> show-stopping limitations like RT-36215) and the Oracle guy 
>>>>>> offered to
>>>>>> relay our concrete questions to the right people, which he did.
>>>>>> The answer we got contained one thing that really was a bit of a 
>>>>>> shock and
>>>>>> I would like someone to either confirm this or clear up a 
>>>>>> misunderstanding.
>>>>>> The statement was that private APIs will not be available in JDK 
>>>>>> 9 due to
>>>>>> modularity restrictions. If that is the case and we no longer 
>>>>>> have the
>>>>>> ability to build temporary workarounds using private APIs (which 
>>>>>> in our
>>>>>> case is controllable as we ship the JRE with our product), I 
>>>>>> would probably
>>>>>> have to stop any development going into the direction of JFX as 
>>>>>> we will
>>>>>> probably have to use 9 at some point because many things now 
>>>>>> scheduled for
>>>>>> 9 will not get fixed in 8 and we will most likely still need 
>>>>>> workarounds
>>>>>> using private API, at least that's what my current experience 
>>>>>> with JFX
>>>>>> tells me.
>>>>>> Please tell me that this was a misunderstanding (maybe meant for the
>>>>>> general case where one does not ship the JRE) or a 
>>>>>> non-engineering source
>>>>>> that simply made mistake.
>>>>>> Best regards and thanks in advance,
>>>>>> Robert

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