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From Edward Drapkin <edwa...@wolfram.com>
Subject Re: question about inline function in java
Date Wed, 03 Nov 2010 09:36:27 GMT
On 11/3/2010 3:08 AM, Li Li wrote:
> hi all
>      we found function call in java will cost much time. e.g replacing
> Math.min with a<b?a:b will make it faster. Another example is lessThan
> in PriorityQueue when use Collector to gather top K documents. Yes,
> use function and subclass make it easy to maintain and extend. in
> C/C++, we can use inline fuction to optimize. What about java? I see
> many codes in lucene also inline many codes mannully.
>     such as implmented hash map in processDocument,
> SegmentTermDocs.read  "// manually inlined call to next() for speed".
>     Is there any compiler option for inline in java? Or we may hardcode
> something for time consuming tasks
>
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The JVM does optimizations like this with its JIT compiler, which 
operates at runtime and optimizes "hot spots" in the execution of the 
application.  Some resources you might want to look at:

http://en.wikipedia.org/wiki/Just-in-time_compilation

http://java.sun.com/developer/onlineTraining/Programming/JDCBook/perf2.html

http://java.sys-con.com/node/1118894

Thanks,
Eddie

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