Not able to turn off G1 GC in JDK-9 preview builds?

[Attila-Mihaly Balazs]

Thank you all for the quick reply. And yes, disabling G1 GC *and* enabling
a different GC works as expected on JDK9. Sorry for not thinking about this
before posting.

Cheers,
Attila

On Thu, Mar 31, 2016 at 12:12 PM, Bengt Rutisson <bengt.rutisson at oracle.com>
wrote:

>
> Just FYI,
>
> With the fix for:
>
> Running with -XX:-UseParallelGC does not turn ParalleGC off
> https://bugs.openjdk.java.net/browse/JDK-8068579
>
> That was recently pushed to JDK 9 you will get the following error message
> if you try to disable the default GC:
>
> Garbage collector not selected (default collector explicitly disabled)
>
> Thanks,
> Bengt
>
>
> On 2016-03-31 10:53, Thomas Schatzl wrote:
>
>> Hi,
>>
>> On Thu, 2016-03-31 at 11:44 +0300, Attila-Mihaly Balazs wrote:
>>
>>> Hello,
>>>
>>> I'm trying to do some benchmarks and was curious what effect using /
>>> not using G1 GC had on it. However I'm unable to turn it off in the
>>> latest JDK-9 beta build (111):
>>>
>> Only trying to disable collectors and not giving an alternative will
>> fall back to the default collector since you need a collector to run.
>> Since G1 is the default collector in this build, it will fall back to
>> G1.
>>
>> The same happens if you only specify -XX:-ParallelGC on the JDK8
>> command line.
>>
>> ~/jdk-9-111/bin/java -XX:-UseG1GC -XX:+PrintFlagsFinal -version |
>>> grep
>>> UseG1GC
>>>       bool UseG1GC                                  :=
>>> true                                {product}
>>> java version "9-ea"
>>> Java(TM) SE Runtime Environment (build 9-ea+111)
>>> Java HotSpot(TM) 64-Bit Server VM (build 9-ea+111, mixed mode)
>>>
>>> With JDK-8 this works as expected:
>>>
>> In JDK8 the default collector is parallel gc.
>>
>> Any pointers as to what my be the issue? I understand that there is a
>>> push to use G1 GC by default in Java 9, however it was my
>>> understanding that the previous GC algorithms will still be
>>> available.
>>>
>> Explicitly enable a different collector, e.g. -XX:+UseParallelGC.
>>
>> You do not need to specify -XX:-Use<default>GC if you want to enable a
>> different collector.
>>
>> Thanks,
>>    Thomas
>>
>>
>