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From Matthias Seidel <matthias.sei...@hamburg.de>
Subject Re: Increase minimum Java version from 5 to 7/8 ?
Date Sun, 09 Jul 2017 16:15:16 GMT
Am 09.07.2017 um 18:07 schrieb Damjan Jovanovic:
> On Sun, Jul 9, 2017 at 5:44 PM, Matthias Seidel <matthias.seidel@hamburg.de>
> wrote:
>
>> Hi Damjan,
>>
>> I can only comment on a non-technical POV...
>>
>> Am 09.07.2017 um 14:53 schrieb Damjan Jovanovic:
>>> Hi
>>>
>>> Currently our Java policy [1] mandates a baseline of Java 5, which was
>>> released in 2004, and was EOL from 2008; even paid Oracle customers
>> stopped
>>> getting updates in 2015 [2].
>> That page was last updated in 2008, so it might definitely need an
>> overhaul. ;-)
>>
>>> There are many language and class library improvements in later versions
>> of
>>> Java that we would benefit from in AOO, and if there are no objections, I
>>> would like to increase the minimum version to 7, if not 8.
>> At least the OS/2 port still relies on Java 6
>> [http://trac.netlabs.org/java].
>> But I think the support is still at beta stage...
>>
>>
> What is the status of our OS/2 support?

We should ask Yuri Dario for that... ;-)
Support for Java is still experimental I think.

>
> The language features are the most important, and it should be possible to
> use Java 7 language features while only using Java <= 5 APIs, and build
> into Java 5 compatible class files, as long as javac (ie. the JDK) is from
> Java >= 7.
>
> But even if it isn't, since class files are the same on all platforms, it
> should be possible to jerryrig a fake "javac" on OS/2, that compiles the
> java file on a remote javac 7, and then downloads the Java 5 compatible
> class file.
>
>
>>> Java 7 would give us the badly needed try-with-resources feature, better
>>> type inference for generics, and Java 8: lambdas and method references,
>>> better java.util collections and lambda-based APIs for them, unsigned
>>> integer arithmetic, etc.
>>>
>>> The only possible downside I see is that the few alternative JVMs that do
>>> exist, tend to only work with older version of Java, for example, the
>>> Apache Harmony class library used in earlier versions of Android only
>>> supported Java 5, GNU Classpath also 5, CacaoVM only supports 6 [3].
>>> Alternative Java implementation aren't relevant to desktop users
>>> (x86/amd64/sparc) any more, since OpenJDK provides free/open-source JVMs
>>> for those, but other platforms and more exotic use cases do need them,
>> eg.
>>> the ARM JVM is only available from Oracle as a commercial product, and
>> the
>>> BugVM project that compiles Java to native code for the iPhone, uses the
>>> Harmony-based Android library.
>>>
>>> Having said that, there are ways to compile most Java 7 code into Java 5
>>> classes. For example try-with-resources compiles into a normal
>>> try-catch-finally, with calls to the Exception.addSuppressed() API that
>>> only exists on Java 7, but the class file can be changed to eliminate
>> them;
>>> I already have a tool that does this. So I guess it's only 8 that's
>>> controversial, as it's lambdas compile into "invokevirtual" instructions,
>>> which didn't exist prior to Java 7.
>>>
>>> Anyway I am proceeding with (uncommitted) development under the
>> assumption
>>> at least 7 is ok, and will revisit with 8 if possible. Please object soon
>>> if you do :-).
>> I still have problems to build AOO for Windows with Java 8.
>> One user mentioned a problem with JavaDoc due to an API change in Java 8.
>> [http://blog.joda.org/2014/02/turning-off-doclint-in-jdk-8-javadoc.html]
>>
>>
> You must be building the 4.1 branches. Trunk has been building perfectly
> with Java 8 for years, since I patched the Javadoc issues we had.

Yes, I am building 4.1 branch...
But with trunk I get other errors regarding gtest... ;-)

Would it be possible to backport your patches? Otherwise I will continue
to build 4.1.4 with Java 7.

Regards, Matthias

>
>
>> Regards, Matthias
>>
>>> Damjan
>>>
>>> References:
>>> [1] https://wiki.openoffice.org/wiki/Policies/Java_Usage
>>> [2] https://en.wikipedia.org/wiki/Java_version_history
>>> [3] https://en.wikipedia.org/wiki/Comparison_of_Java_virtual_machines
>>>
>>
>>



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