> On 15 Oct 2015, at 05:00, Xueming Shen <xueming.s...@oracle.com> wrote: > > I'm not sure if it is a good idea, from performance perspective, to add a > "versionEntry" field into the JarEntry > to support this feature, given most of the jar files might not be > multi-release-jar aware, and the Jar input& > output streams dont work with a multi-release jar directly. Why should they > all pay a runtime price for it. If > we really have to add an extra field, the JarFileEntry might be a better > place, and it might be desired to > define a new subclass JarFileEntryMR to use when the MR is enabled, instead > of adding directly into the existing > JarFileEntry. >
According to jol there is currently space available due to alignment. If there was not it would add about 4% in direct instance size. But the actual footprint is likely to be chunkier because of the string character storage for the name so the % increase in size would be smaller e.g. perhaps on average < 2% which might be ok given that i presume such entries are unlikely to be cached. So i am not concerned about the size. If there was a way to design it to avoid modification of existing classes all the better, but i dunno if it is possible. Steve will surely know more. Paul.
