UrlResource computes a cleanedUrl in its constructor, but only uses it in a small number of methods (e.g. hashCode()). It has some String manipulations in it that can be expensive, so it might make sense to compute it lazily.
Some benchmarks (instantiate a FileUrlResource and check if it exists()):
class method median mean range
com.example.bench.ResourceBenchmark lazy 441889.554 460384.372 16671.778
com.example.bench.ResourceBenchmark default 415765.658 440910.870 18462.893
I think the fact that the median comparison is much more dramatic is probably because of garbage collection, which is quite noisy, and would be more common in the default case.
Spring Boot computes quite a few of these FileUrlResources on startup as it searches for application.properties files. The difference is just about noticeable (a few milliseconds on startup, and fewer GC failures).
UrlResourcecomputes acleanedUrlin its constructor, but only uses it in a small number of methods (e.g.hashCode()). It has someStringmanipulations in it that can be expensive, so it might make sense to compute it lazily.Some benchmarks (instantiate a
FileUrlResourceand check if itexists()):I think the fact that the median comparison is much more dramatic is probably because of garbage collection, which is quite noisy, and would be more common in the default case.
Spring Boot computes quite a few of these
FileUrlResourceson startup as it searches forapplication.propertiesfiles. The difference is just about noticeable (a few milliseconds on startup, and fewer GC failures).