Hmmm..... I watched a you tube video that says you had to download Java before downloading the Vassal engine. You mean I can't believe everything I see on the internet ?
The Youtube video probably relates to older versions of VASSAL. There has been a lot of ongoing development of VASSAL in the past few months.
As said before by 'zgrose', with VASSAL v3.4.x (with v3.4.12 being the most current VASSAL version and a VASSAL v3.5 beta version already available for testing as of 9. January 2021), you no not need an extra JAVA installation as JAVA is an inherent part of the VASSAL package. That said, if new VASSAL versions are released, these might include updates of the inbuilt JAVA versions as well.
Bottom line:
With VASSAL v3.4.x, you do not need to install any independent JAVA versions.
Running VASSAL v3.4.x, the current VASL version to go with it is VASL v6.6.1 (as of 9. January 2021).
If you use older VASL versions (up to VASL v6.5.1), then you need an older VASSAL version (VASSAL v3.2.17).
For VASSAL v3.2.17, you DO need an independent JAVA installation - and an old and outdated one at that.
I think the JAVA version required by VASSAL v3.2.17 is JAVA 8 (!). I
think the latest version available of the outdated JAVA 8 is 'built 221'. Note, though, that the current JAVA version is 15!
Bottom line:
Do yourself a favor and forget about VASSAL v3.2.17 and VASL v6.5.1 and use the current versions of both which will also save you the fuss of finding/using much outdated JAVA versions.
von Marwitz