PSA: You can now use "var" in when writing Java

[Andrew Grieve]

As of this commit from July 27, we've switched Android java compiles from Java 8 -> Java 11.

This does not change what library methods are available. It only changes what language features you can use, and what the .class file bytecode looks like before it's converted into DEX. AFAICT, the only meaningful language difference is the ability to use "var", which is the Java equivalent of C++'s "auto".