plasma-umass / doppio_jcl Goto Github PK

Currently, DoppioJVM issues a network request for every individual uncompressed class file it needs to load. This is awful when you are not on a fast connection.

It would be much better to package the JCL into multiple jar files, perhaps through subdividing the packages. I will need to do an experiment to see what packages are touched by which programs, to see if there's a sensible separation that can minimize network time.

• Enumerate GUI-related packages (e.g. .awt. and .swing.), and segment off to a separate JAR file.
• Avoid integrating ecj's source into java_home. There's no need for that anymore, now that Doppio has built-in JAR file support.
• Experiment to determine other useful segmentations.

We have a custom Provider for security-related things for DoppioJVM. We should appropriately modify the JCL's java.security properties file to use this as the default provider, which avoids eagerly initializing the DoppioProvider class.

• Executables in bin
• man pages
• *.so files

Command used:

advzip --recompress -4 --iter 4 rt.jar

This is using the 1.18 version of advancecomp that comes with ubuntu 14.04 LTS. Newer versions might give better compression.

Also increasing the number of iterations might improve compression.

Note: it takes a long time to compress (half an hour on my system for rt.jar). But according to the zopfli documentation, it has none to negligible impact on decompression.