[PATCH] 4851444: Exposing sun.reflect.Reflection#getCallerClass as a public API in Java 8

[Remi Forax]

On 09/20/2013 11:57 AM, Jörn Huxhorn wrote:
> On 20. September 2013 at 11:35:24, Peter Levart (peter.levart at gmail.com) wrote:
> On 09/20/2013 10:57 AM, Jochen Theodorou wrote:
>> Am 20.09.2013 09:28, schrieb Nick Williams:
>> [...]
>>> This is all well and good, but some of us just need a simple array.
>>> This seems like over-engineering. I just want an array of
>>> StackFrameInfos/StackTraceFrames.
>>   
>> if you need the full stack, then misusing a Predicate and a dummy
>> Consumer to collect everything looks a lot like not intended use. The
>> intended inability of lambdas to write to local variables outside the
>> lambda is not helping here to avoid anonymous inner classes. So what
>> was a simple method call, will look really awful - I agree.
> List<StackFrameInfo> frames = new ArrayList<>();
> Thread.walkStack(frames::add);
>
> No so awfull.
>
> Regards, Peter
> This is precisely what I mean. Yes, it has a nice syntax but it will perform worse than simply working on a StackTraceFrame[].

why ?

>
> It's not that awful but it's the construction of an additional ArrayList instance and n additional method calls plus additional gc heat.
>
> We are talking about code that will be executed for every single log statement, i.e. millions/billions of times. This *will* add up and it *will* make a significant difference. This isn't premature optimization either - it's just a very hot hotspot.
>
>
>
> Joern

Rémi