Java doesn't seem a bad choice because if one sticks to the basics probably everybody can figure out what a simple program does. Smalltalk, I wonder how many people here ever read a Smalltalk source file [1]. Lisp, maybe more, at least to look once at all those funny parentheses (disclaimer, I wrote my fair share of Lisp but I know the effect it does on most people.)
[1] One random Smalltalk project from the list of trending Smalltalk repositories on GitHub https://github.com/svenvc/zinc
I don't really know Java. But I know C, and Java looks enough like C that I can get what Java code is trying to do.
Personally, I've never learned any language with similar-enough syntax to BASIC, to understand what a (real, non-trivial) BASIC program is trying to do. Would I recognize a BASIC subroutine if I saw one? Probably not.
And it's not about a language having "less" syntax, either, but rather about it having very few syntactic features that're unfamiliar. Smalltalk is a rather large novelty the first time you see it. (`ifTrue`? You mean I've got to use closures to branch?)
Java has so little syntax—and yet what little syntax it has is C-ish—that it's mutually intelligible to everybody from programmers who only know C, to programmers who only know Haskell. (Maybe not to programmers who only ever learned 6502 assembler, but they have their own humor books published 40 years ago.)
(Is there a term for this in linguistics? A measure of the eigenvector of mutual intelligibility a language has to all other spoken/written languages?)