ZipOutputStream and nested zip files

[Stephanie Smith]

I want to create a zip file that itself contains
zip files. I'm assuming that I have to create the
nested zip file on the file system. And then add it
to the main zip file via ZipOutStream's putNextEntry().
And basically read in the nested file and write it out to the
main zip file?
Is this true? wanted to make sure there wasn't some sort
of trick that would make this easier.

[Valentin Crettaz]

Hi Stephanie,
Basically a ZIP file is just another file. So, if you want to include ZIP files in another ZIP file, the way you proceed is correct. You first have to create the nested ZIPs and then add those to the main ZIP.

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Valentin Crettaz
Sun Certified Programmer for Java 2 Platform

[Peter Tran]

Stephanie,
Let me first ask why are you creating nested zip? First, it only complicates thing and you're not going to get better compression. In fact, if you take a zip file and keep on nesting it, your zip file will eventually just grow, because the zip algorithm cannot compress the original content anymore, but it does have to add header information. So all your doing with each nesting is just zipping a little bit of header information.
-Peter

[Valentin Crettaz]

I agree with you Peter, but maybe what Stephanie wants is just to group different ZIP files together in one to facilitate download or I don't know...
Let us know Stephanie why you are zipping ZIPs

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Valentin Crettaz
Sun Certified Programmer for Java 2 Platform

[Stephanie Smith]

Sounds good, thanks for all the advice. We have nested zips mainly to provide a way to group information. Users can nest
files that are related in a nested zip. We allow the
calling application to decide whether or not to do this.
By default we do not create nested zips, but again, we do
allow for it.
thanks!

[Valentin Crettaz]

That's what I thought... Zipping for groupping is a good idea. That's exactly what the JAR files are for by the way...
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Valentin Crettaz
Sun Certified Programmer for Java 2 Platform