Java is the opposite of boring. It lacks basic fundamentals such as algebraic data types and pattern matching. You will be kicking and screaming the whole ride.

A boring language would be a language where you aren't triggered/bothered by its basic ergonomics and hygiene. In Java, you must translate discrete variants into dogmatic OO paradigm instead of using language primitives.

Thanks to Java's poor design, it's fundamentally a hazard and a land mine thanks to null not being first class in type system. The use of null as a value inhabiting any type should result in a slap in the face upon opening a pull request (until Java adopts type-safe optionals like Kotlin)

P.S. Switch expressions and sealed interfaces aren't there yet, Kotlin and Scala are still the only options if you are imprisoned to JVM.

I have the same opinion about Java and I hesitated as well before starting to read the book, so I'll use either Kotlin or common lisp.