[Engine-devel] java 1.6 compatibility no more?

[Livnat Peer]

On 19/07/12 14:41, Juan Hernandez wrote:
> On 07/19/2012 01:39 PM, Yair Zaslavsky wrote:
>> On 07/19/2012 02:31 PM, Vojtech Szocs wrote:
>>>> Don't we need that (the source part) to avoid Java 7 syntax in GWT code?
>>>
>>> That's a very good point.
>>>
>>> In general, GWT compiler supports Java 5 syntax (note that there are no language changes between Java 5 and 6). For this reason, our frontend code should be compliant with Java 5. If someone uses new Java 7 language features in frontend code, GWT compiler will throw an error and the build will fail.
>>>
>>> So the 'Java 5 only' limitation applies to frontend code and any other code (e.g. shared modules) that is directly referenced by frontend code. This shouldn't affect the backend, however.
>>>
>>> We could do something like this:
>>>
>>> - let oVirt root POM declare source and target compliance to Java 7
>>> - let frontend modules POM (frontend/webadmin/modules/pom.xml) declare source compliance to Java 5 (or 6)
>>>
>>> (note that target compliance can be left to Java 7 since frontend compilation results in JavaScript code)
>>>
>>> What do you think?
>>>
>>> Vojtech
>>
>> +1 - I really like this idea!
> 
> +1 from me as well.


There are two calls to make when it comes to JDK7 (regardless of GWT -
excuse me for taking this discussion some steps backwards)

1. Are we running with JRE 7?
The answer is yes we agreed on that a few months ago.

2. Are we using code syntax which is incompatible with JDK6?

I think the answer to the above should be no (at least for now - maybe
until the next ovirt release?).

There are two reason off the top of my head for that -
If we find an issue it is easier to compare the issue on JDK6 vs. JDK7
if the code compiles on both.

Open JDK7 is out for a year or so, It was packaged for fedora only in
March  2012, I am not sure how ofter it is used in 'production'
environment, I think we should at least keep ourself the option to
roll-back in case we need it.


Livnat



> 
>>> ----- Original Message -----
>>> From: "Juan Hernandez" <jhernand at redhat.com>
>>> To: "Vojtech Szocs" <vszocs at redhat.com>
>>> Cc: "Yair Zaslavsky" <yzaslavs at redhat.com>, engine-devel at ovirt.org
>>> Sent: Thursday, July 19, 2012 11:01:00 AM
>>> Subject: Re: [Engine-devel] java 1.6 compatibility no more?
>>>
>>> On 07/19/2012 10:09 AM, Vojtech Szocs wrote:
>>>>> As I previously emailed - JDK7 already fixed a known issue with ldap and
>>>>> DNS ,and made one of my patches at gerrit redundant.
>>>>> Why not enjoy the bug fixes?
>>>>
>>>> I agree, but in that case, why not switch to '1.7' Java source/target compliance for oVirt Maven build as well?
>>>>
>>>> If JDK6 cannot be used for building oVirt (because of missing Java 7 APIs, because of LDAP/DNS issues in JDK6, etc.), we should also update our Maven POM files. Currently, when I import oVirt projects into Eclipse (using Eclipse Maven plugin), I'm getting compile errors on 'bll' project. This is because our Maven POM files declare '1.6' Java source/target compliance.
>>>>
>>>> Juan - you are right, but for me, it sounds quite strange to have '1.6' Java source/target compliance for Maven build, and use JDK7 to do the build.
>>>
>>> Don't we need that (the source part) to avoid Java 7 syntax in GWT code?
>>>
>>>> ----- Original Message -----
>>>> From: "Yair Zaslavsky" <yzaslavs at redhat.com>
>>>> To: engine-devel at ovirt.org
>>>> Sent: Thursday, July 19, 2012 7:59:45 AM
>>>> Subject: Re: [Engine-devel] java 1.6 compatibility no more?
>>>>
>>>> On 07/18/2012 08:21 PM, Juan Hernandez wrote:
>>>>> On 07/18/2012 06:33 PM, Vojtech Szocs wrote:
>>>>>> In fact, for both backend and frontend, Maven effective POM contains:
>>>>>>
>>>>>> <artifactId>maven-compiler-plugin</artifactId>
>>>>>> <configuration>
>>>>>>   <source>1.6</source>
>>>>>>   <target>1.6</target>
>>>>>> </configuration>
>>>>>>
>>>>>> Therefore, according to Maven POM files, oVirt should be build-able using Java 6, but it's not. (?)
>>>>>
>>>>> These maven settings just tell the java compiler to accept Java 6 syntax
>>>>> only and to generate a Java 6 compatible .class file format, but they
>>>>> don't restrict the set of APIs that can be used.
>>>>>
>>>>>> The problem is in backend/manager/modules/bll: StorageDomainCommandBase class uses new Java 7 Long.compare() static method.
>>>>>>
>>>>>> I think we should decide if we want to be compliant with Java 7, or submit a patch that uses Java 6 API (Long.compareTo instance method).
>>>>>>
>>>>>> Vojtech
>>>>
>>>> As I previously emailed - JDK7 already fixed a known issue with ldap and
>>>> DNS ,and made one of my patches at gerrit redundant.
>>>> Why not enjoy the bug fixes?
>>>>
>>>>>>
>>>>>>
>>>>>> ----- Original Message -----
>>>>>> From: "Laszlo Hornyak" <lhornyak at redhat.com>
>>>>>> To: "engine-devel" <engine-devel at ovirt.org>
>>>>>> Cc: "Vojtech Szocs" <vszocs at redhat.com>
>>>>>> Sent: Wednesday, July 18, 2012 5:43:34 PM
>>>>>> Subject: java 1.6 compatibility no more?
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> It may be a historic moment, but for a few hours oVirt engine is no longer building on java 1.6.
>>>>>> Is this intentional?
>>>>>>
>>>>>> Laszlo
> 
>