Java is a combination of language syntax, platform libraries and runtime.

Android uses the language syntax but does not use the platform libraries or the runtime. Consequently Android is not "Java". It's particularly inappropriate to draw runtime performance comparisons based on Android when it doesn't use the Java runtime.

So "how that Java works" is not a secondary issue. I also gave you an example of another toolkit which lets you write something using the Java language syntax but produces output which is obviously not "Java".