Java 8 has complex situation on the unsupported XP. Back in early versions, the installer will warn user that it require newer windows and may not functioning as specified if user proceed. Indeed things start to break one by one, as a software platform runtime it might not obvious when it works or not that's until we ask specific broken component otherwise JVM continue on happily.
These are several component that I notice breaks on XP.
U111: the last version where JavaFX component works
U241 and U242: the last version where crypto API works (sunmscapi), newer version require NCrypt (part of MS CNG alongside BCrypt)
U261/U262: add TLS 1.3 support (jsse) and since it is related to sunmscapi it's pointless for XP, also in this version java executables no longer runnable on XP as their PE header set against NT6. It can be fixed to run on XP but doing so will break digital signature.
In my experiment we could mix newer java binary with older working component e.g. JavaFX or Crypto API, as long as they replaced as whole (dlls and jars).
Another complication, U151/U152 is the last installable version and U201/U202 is the last Oracle version which allow commercial works. On recent non-installable version user can opt to use tar.gz format (manual install) which need manual java -jar invocation from cmd prompt.
The alternative openjdk aren't that good either, so far only AdoptOpenJDK provide 32-bit binary and they dont bundle brower plugin or JavaFX furthermore all version has PE header set to NT6 so they are not runnable on XP.
Java 8 scheduled to be supported until 2026 for openjdk and 2030 according Oracle. Too bad XP version ended too soon.
AFAIK now the only still updated Java that works on XP 32-bit is IBM J9 Java 7 which can be downloaded separately from Websphere albeit not as installer (need free account login) and this will last until 2022. Not much I would say.