5 Replies Latest reply: Oct 23, 2012 10:18 PM by EJP RSS

    Why are all jar files not compressed in the JRE installer?

    969947
      I used 7zip to unpack jre-6u12-windows-i586-p.exe (Oracle JRE Installer). On unpacking, I got a core.zip, a zipper.exe and a few other files.

      Again on exploding core.zip I found a few things. core.zip contains all the jar files just like it would be after installation except for 7 jar files.

      charsets.jar
      deploy.jar
      javaws.jar
      jsse.jar
      localedata.jar
      plugin.jar
      rt.jar

      Instead of these jar files there exists the corresponding packfiles

      charsets.pack
      deploy.pack
      javaws.pack
      jsse.pack
      localedata.pack
      plugin.pack
      rt.pack

      I think these are files created by pack200.exe & unpack200.exe is run on them after installation to create the corresponding jar files.

      So now I have a few questions

      Why are only these 7 files run through pack200.exe. I assume its because they are bigger than other files. But it wouldn't take that much effort to pack all jar files & unpack them after installation.

      The .pack extension suggests that these are packed but not gzipped. Again why would Oracle not do a gzip also? for eg with rt.jar packing reduces size from 45 MB to 12 MB, while adding gzip also reduces it to 6 MB.

      Edited by: 966944 on Oct 22, 2012 8:19 AM