4206909 - adding Z_SYNC_FLUSH support to deflaters

[Xueming Shen]

Martin Buchholz wrote:
> The obvious alternative to built-in zlib
> in the jdk is jzlib
>
> http://www.jcraft.com/jzlib/
>
> a pure-java implementation of zlib
> under an apparently GPL-compatible license
> that does support flush modes.
> Some people are using it for that reason.
>
> Non-scientific benchmarks at Google suggest
> it is twice as slow as JDK Deflater,
> so we may not want to throw out C zlib just yet.
>
>   
jzlib owner claims the number one reason we have zlib in this world is 
java deflater does
not export zlib's sync_flush and the previous maintainer refused to add 
it after so many
years:-)

no, you can't throw out the c zlib even after we have a java version 
benchmarked
faster (in 8?),  vm and pack still need the native version.