For Java I used https://www.thoughtco.com/reserved-words-in-java-2034200 but Wikipedia lists 51. I'm too lazy to actually diff it.
For Javascript I used https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... and fudged the numbers a bit. There are future reserved words, but I didn't iinclude them because there's no point in memorizing them. Now that I look in detail that list also doesn't include "true", "false", and "null".
39 listed here https://tc39.es/ecma262/2020/#sec-keywords-and-reserved-word...
51 listed here https://docs.oracle.com/javase/specs/jls/se15/html/jls-3.htm... with a bunch of non keywords listed below, of which true false and null are also reserved
Where did you find these numbers? I'm trying to find them but I can only find the Ecmascript and the number appears way higher