More memory-efficient internal representation for Strings: call for more data

charlie hunt charlie.hunt at
Tue Dec 2 22:18:26 UTC 2014

Potentially in the future. It has been on a list of candidate enhancements for quite some time.

As Aleksey just mentioned in his response, (he beat me to the punch), that work is not in scope as part of this project.

Should also mention that the work from this project would not prohibit such an enhancement.



> On Dec 2, 2014, at 4:13 PM, Vitaly Davidovich <vitalyd at> wrote:
> Any consideration towards removing the char[] (or byte[]) indirection altogether? .NET for example stores the bytes inline with the instance.
> Sent from my phone
> On Dec 2, 2014 4:59 PM, "Aleksey Shipilev" <aleksey.shipilev at <mailto:aleksey.shipilev at>> wrote:
> Hi,
> As you may already know, we are looking into more memory efficient
> representation for Strings:
> <>
> As part of preliminary performance work for this JEP, we have to collect
> the empirical data on usual characteristics of Strings and char[]-s
> normal applications have, as well as figure out the early estimates for
> the improvements based on that data. What we have so far is written up here:
> <>
> We would appreciate if people who are interested in this JEP can provide
> the additional data on their applications. It is double-interesting to
> have the data for the applications that process String data outside
> Latin1 plane. Our current data says these cases are rather rare. Please
> read the current report draft, and try to process your own heap dumps
> using the instructions in the Appendix.
> Thanks,
> -Aleksey.

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