Inflater/Deflater improvements

Xueming Shen Xueming.Shen at Sun.COM
Mon May 18 20:21:25 UTC 2009

Performance of Inflater/Deflater does not change the class loading 
performance from
jar files bundled with JDK/JRE, they have been "uncompressed" after 


Ulf Zibis wrote:
> Am 04.05.2009 23:38, Martin Buchholz schrieb:
>> I think many people will be interested in performance improvements
>> in Inflater/Deflater.  I may have time to help review.
> Yes, there is also interest from charset de/encoding side. See:
> Current charset mapping tables are hosted as huge String constants 
> inside charset classes. Hosting them as resource data files would 
> would avoid ~50 % disk-footprint wastage of the charsets.jar. 
> Additionally sharing of overlapping charset mapping data would become 
> manageable. Currently we only have ClassLoader#getResouceAsStream() to 
> load such data files, but we can't use it, because the underlying 
> buffered stream is too slow in respect of JVM startup time. We need 
> fast nio direct buffer access via java.nio.channels.Channel to load 
> the data from charsets.jar.
> So improving performance of jar/zip file access would be much 
> appreciated. :-)
> -Ulf

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