Java finally admits to not having the courage of its convictions-- do what I say (write in pure abstraction), not what I do (peek and poke at the JVM like it's C because that's faster). https://blogs.oracle.com/javamagazine/the-unsafe-class-unsafe-at-any-speed

Your Java Virtual Machine can run any Java code as long as it meets the JVM spec!*

* but of course your JVM has to look and work internally almost exactly like the oracle one to support the modern JDK

From the oracle blog above: “However, in practice, everyone knows that no Java developer is really willing to significantly degrade performance simply to maintain strict adherence to the Java spec.”

“Only a dumbass would actually use Java!” — The people who make Java

(I grant that this thread has a niche audience appeal)