Performance issue when updating to XSteam 1.4.9

[Ralf Purnhagen]

After upgrading from XStream 1.4.8 to 1.4.9 i observed a huge degradation of the performance for XML (un-)marshalling. XStream suddenly got 50-100% slower.

I created a sampling with VisualVM. In my opinion the reason for the perfomance degradation is the new code for the fix "Implicit collection declaration is erroneously inherited or propagated to hidden field of same name." in the class ImplicitCollectionMapper. This fix leads to massive calls to Class.getDeclaredField, which is extremly expensive.

Would it be a possible, to cache the results of the getDeclaredField call or do you have any other idea for a performance optimization?

Regards,
Ralf

[Jörg Schaible]

Hi Ralf,

Well, in general XStream 1.4.9 should have been faster ;-)

Can you open an issue about this at GitHub? Then I can investigate.

Cheers,
Jörg

[Ralf Purnhagen]

Hi Jörn,

in general it is 10 to 15% faster. In my case not.

I just opened a pull request suggesting a cache for field names. Please have a look at it.

Regards,
Ralf

[Ralf Purnhagen]

Issue opened on GitHub: https://github.com/x-stream/xstream/issues/61

[Jörg Schaible]

Hi Ralf,

Ralf Purnhagen wrote:

> Issue opened on GitHub: https://github.com/x-stream/xstream/issues/61

I've seen the PR and basically it's OK, but I'll try to use an internal
already availabel cache for it. Nevertheless I face currently some hardware
problems, therefore my coding activities stalled a bit.

Cheers.
Jörg