npub1p4yf3utz0gdc43v2vzpfx7k5vqc7mr3mrnr3qm2vm87pdp8myu9qkpl8vj (npub1p4y…l8vj)
It was October 2009: https://en.wikipedia.org/wiki/Java_version_history
J2SE 1.4 was followed up with J2SE 5.0 (1.5 became 5.0)
After 5.0 came 6, and they dropped even the pretense of a decimal point.
Oh wow, *exactly* a decade and a half ago!