> Every system capable of running Java also has its own trust store No, they don't: https://en.wikipedia.org/wiki/Java_Card https://en.wikipedia.org/wiki/Java_

> Every system capable of running Java also has its own trust store No, they don't: https://en.wikipedia.org/wiki/Java_Card https://en.wikipedia.org/wiki/Java_Card there are also other examples of java running in embedded and semi-embedded scenarios where a TZDB and a SSL trust store would not be guaranteed by the host.