Re: [Dev] Is there a hard and fast rule to chose java 8 streams over for loops

[SajithAR Ariyarathna]

Its very hard to come-up with a hard & fast rule on when to use Stream
API/Lambda or traditional loops. However, in the Carbon platform we have
come-up with a rule of thumb for such scenario.

*Always give the priority to code readability*.


It doesn't matter whether you use Streams, Lambda, or traditional loops,
always write clean, readable, self-descriptive code. *Only exception is
performance*. If your code is performance critical, then you are allowed to
do optimizations that might lead to a more complex code. Even in such
situation, always try to maintain the code readability at a high level
(comments can be a good tool here).

Why Code Readability Matters? [1]

[1] https://dzone.com/articles/why-code-readability-matters

Thanks.


On Fri, Apr 7, 2017 at 12:16 PM, Vidura Nanayakkara 
wrote:

> Hi,
>
> Blog [1]  compares
> streams and loops for arrays and lists for different types of operations
> and is worth taking a look at. Blog [2]
> 
>  discusses
> when to use parallel streams which are also worth taking a look. IMO this
> depends according to the scenario you are left to deal with. For instance,
> in Carbon UUF we use loops instead of streams since the datasets we
> consider are relatively small (UUF is performance critical). There are also
> instances where we use streams where the possible performance drop due to
> using streams is small considering the code readability (the code is
> complex when loops are used).
>
> [1] Loops vs Streams 
> [2] Parallel stream processing in Java 8 – performance of sequential vs.
> parallel stream processing
> 
> [3] What's Wrong in Java 8, Part III: Streams and Parallel Streams
> 
>
> On Fri, Apr 7, 2017 at 9:02 AM, Jude Niroshan 
> wrote:
>
>> I agree with Tharika. It's more important to know that streams can be
>> considered when you need parallel processing done. Being said that, usage
>> has to be careful about the mutable operations. AFAIK, streams are good at
>> map reduction over the traditional for loops. It is more easy to manipulate
>> the collections. But it is not advisable to always go for streams.
>>
>> On Thu, Apr 6, 2017 at 8:54 PM, Pumudu Ruhunage  wrote:
>>
>>> Hi, IMO for less number of iterations/elements for loops are much
>>> efficient, and when number gets higher both are performing with similar
>>> efficiency. Advantage of parallel streams shows up when number of elements
>>> increases and cost of each iteration increases.
>>> Therefore, usage of streams/loops is highly dependent of the scenario
>>> and can not suggest either without proper knowledge of the scenario,
>>> especially for critical paths.
>>>
>>> Regards,
>>>
>>> On Thu, Apr 6, 2017 at 5:19 PM, Tharika Madurapperuma 
>>> wrote:
>>>
 Hi Rajith,

 IMO Java streams should not be used always as a practice. It is not
 a silver bullet. There can be issues in performance in some cases as you
 have pointed out.

 One of the main advantage of using streams is when the logic of
 looping is quite complex and involves different operations on collections
 together, so that it can improve readability and understandability. But at
 the same time it can result in new and subtle bugs if we are not careful
 enough [1].

  The performance aspect of streams vs loops depends on the type of
 the collection and the situation they deal with. This performance
 difference can sometimes be negligible. Hence we cannot completely go with
 one against another.

  So IMHO we can consider using streams only when necessary based on
 our requirement and use loops where it deserves.


 [1] https://blog.jooq.org/2014/06/13/java-8-friday-10-subtle-mis
 takes-when-using-the-streams-api/


 Thanks,
 Tharika.


 On Thu, Mar 30, 2017 at 12:01 PM, Rajith Roshan 
 wrote:

> Hi all,
>
> Most of our C5 development have used java8 streams api frequently more
> than the for loops.
> But there are some research have done to compare the performance of
> streams api compared to for loops. They have shown that stream API is slow
> compared to for loops in many scenarios (even for parallel streams). 
> [1][2]
>
> Is there any proper guidance to use which one over the other or are we
> using streams as a practice in C5 development
>
> [1] - https://blog.jooq.org/2015/12/08/3-reasons-why-you-shouldn
> 

Re: [Dev] Is there a hard and fast rule to chose java 8 streams over for loops

[Pumudu Ruhunage]

Hi, IMO for less number of iterations/elements for loops are much
efficient, and when number gets higher both are performing with similar
efficiency. Advantage of parallel streams shows up when number of elements
increases and cost of each iteration increases.
Therefore, usage of streams/loops is highly dependent of the scenario and
can not suggest either without proper knowledge of the scenario, especially
for critical paths.

Regards,

On Thu, Apr 6, 2017 at 5:19 PM, Tharika Madurapperuma 
wrote:

> Hi Rajith,
>
> IMO Java streams should not be used always as a practice. It is not a
> silver bullet. There can be issues in performance in some cases as you have
> pointed out.
>
> One of the main advantage of using streams is when the logic of
> looping is quite complex and involves different operations on collections
> together, so that it can improve readability and understandability. But at
> the same time it can result in new and subtle bugs if we are not careful
> enough [1].
>
>  The performance aspect of streams vs loops depends on the type of the
> collection and the situation they deal with. This performance difference
> can sometimes be negligible. Hence we cannot completely go with one against
> another.
>
>  So IMHO we can consider using streams only when necessary based on
> our requirement and use loops where it deserves.
>
>
> [1] https://blog.jooq.org/2014/06/13/java-8-friday-10-subtle-
> mistakes-when-using-the-streams-api/
>
>
> Thanks,
> Tharika.
>
>
> On Thu, Mar 30, 2017 at 12:01 PM, Rajith Roshan  wrote:
>
>> Hi all,
>>
>> Most of our C5 development have used java8 streams api frequently more
>> than the for loops.
>> But there are some research have done to compare the performance of
>> streams api compared to for loops. They have shown that stream API is slow
>> compared to for loops in many scenarios (even for parallel streams). [1][2]
>>
>> Is there any proper guidance to use which one over the other or are we
>> using streams as a practice in C5 development
>>
>> [1] - https://blog.jooq.org/2015/12/08/3-reasons-why-you-shouldn
>> t-replace-your-for-loops-by-stream-foreach/
>> [2] - https://jaxenter.com/java-performance-tutorial-how-fast-ar
>> e-the-java-8-streams-118830.html
>>
>> Thanks!
>> Rajith
>>
>> --
>> Rajith Roshan
>> Software Engineer, WSO2 Inc.
>> Mobile: +94-72-642-8350 <%2B94-71-554-8430>
>>
>> ___
>> Dev mailing list
>> Dev@wso2.org
>> http://wso2.org/cgi-bin/mailman/listinfo/dev
>>
>>
>
>
> --
> *Tharika Madurapperuma*
> Software Engineer | WSO2, Inc.
>
> Email : thar...@wso2.com
> Mobile : +94777875624 <+94%2077%20787%205624>
> Web : http://wso2.com
>
> 
>
> ___
> Dev mailing list
> Dev@wso2.org
> http://wso2.org/cgi-bin/mailman/listinfo/dev
>
>


-- 
Pumudu Ruhunage
Software Engineer | WSO2 Inc
M: +94 779 664493  | http://wso2.com

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Re: [Dev] Is there a hard and fast rule to chose java 8 streams over for loops

[Tharika Madurapperuma]

Hi Rajith,

IMO Java streams should not be used always as a practice. It is not a
silver bullet. There can be issues in performance in some cases as you have
pointed out.

One of the main advantage of using streams is when the logic of looping
is quite complex and involves different operations on collections together,
so that it can improve readability and understandability. But at the same
time it can result in new and subtle bugs if we are not careful enough [1].

 The performance aspect of streams vs loops depends on the type of the
collection and the situation they deal with. This performance difference
can sometimes be negligible. Hence we cannot completely go with one against
another.

 So IMHO we can consider using streams only when necessary based on our
requirement and use loops where it deserves.


[1]
https://blog.jooq.org/2014/06/13/java-8-friday-10-subtle-mistakes-when-using-the-streams-api/


Thanks,
Tharika.


On Thu, Mar 30, 2017 at 12:01 PM, Rajith Roshan  wrote:

> Hi all,
>
> Most of our C5 development have used java8 streams api frequently more
> than the for loops.
> But there are some research have done to compare the performance of
> streams api compared to for loops. They have shown that stream API is slow
> compared to for loops in many scenarios (even for parallel streams). [1][2]
>
> Is there any proper guidance to use which one over the other or are we
> using streams as a practice in C5 development
>
> [1] - https://blog.jooq.org/2015/12/08/3-reasons-why-you-
> shouldnt-replace-your-for-loops-by-stream-foreach/
> [2] - https://jaxenter.com/java-performance-tutorial-how-fast-
> are-the-java-8-streams-118830.html
>
> Thanks!
> Rajith
>
> --
> Rajith Roshan
> Software Engineer, WSO2 Inc.
> Mobile: +94-72-642-8350 <%2B94-71-554-8430>
>
> ___
> Dev mailing list
> Dev@wso2.org
> http://wso2.org/cgi-bin/mailman/listinfo/dev
>
>


-- 
*Tharika Madurapperuma*
Software Engineer | WSO2, Inc.

Email : thar...@wso2.com
Mobile : +94777875624
Web : http://wso2.com


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[Dev] Is there a hard and fast rule to chose java 8 streams over for loops

[Rajith Roshan]

Hi all,

Most of our C5 development have used java8 streams api frequently more than
the for loops.
But there are some research have done to compare the performance of streams
api compared to for loops. They have shown that stream API is slow compared
to for loops in many scenarios (even for parallel streams). [1][2]

Is there any proper guidance to use which one over the other or are we
using streams as a practice in C5 development

[1] -
https://blog.jooq.org/2015/12/08/3-reasons-why-you-shouldnt-replace-your-for-loops-by-stream-foreach/
[2] -
https://jaxenter.com/java-performance-tutorial-how-fast-are-the-java-8-streams-118830.html

Thanks!
Rajith

-- 
Rajith Roshan
Software Engineer, WSO2 Inc.
Mobile: +94-72-642-8350 <%2B94-71-554-8430>
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