String compression was one. tl;dr: the JVM supports Unicode for strings, but uses 1-byte chars for strings where possible (previously it was UTF-16), even thoug

String compression was one. tl;dr: the JVM supports Unicode for strings, but uses 1-byte chars for strings where possible (previously it was UTF-16), even though it's not actually doing UTF-8. Depending on what sort of document you're looking for, you might like either the JEP: https://openjdk.org/jeps/254 https://openjdk.org/jeps/254 or Shipilev's slides (pdf warning): https://shipilev.net/talks/jfokus-Feb2016-lord-of-the-strings.pdf https://shipilev.net/talks/jfokus-Feb2016-lord-of-the-string... Shipilev's website (https://shipilev.net/#lord-of-the-strings https://shipilev.net/#lord-of-the-strings), and links from the JEP above to other JEPS, are both good places to find further reading. (I think I saw a feature article about the implementation of the string compression feature, but I'm not sure who wrote it or where it was, or if I'm thinking about something else. Actually I think it might've been https://shipilev.net/blog/2015/black-magic-method-dispatch/ https://shipilev.net/blog/2015/black-magic-method-dispatch/, despite the title.)