It's probably worth mentioning that the regex-dna test time is kind of incorrect and provides an inaccurate view of what's happening.
Java-8 is using java.util.regex which is written in Java, PHP is passing the regex requests to it's own regex process which is actually a C package and performs a lot faster.
What we're actually comparing here is:
time(java.util.regex) > time(php compilation + c regex package)
PHP's execution performance is highly dependent on whether you are piggybacking the C implementations, or pure-PHP ones. That said, this is still a correct benchmark, if your use case involves a lot of regex.
Java-8 is using java.util.regex which is written in Java, PHP is passing the regex requests to it's own regex process which is actually a C package and performs a lot faster.
What we're actually comparing here is:
time(java.util.regex) > time(php compilation + c regex package)