Java 8+ is basically a declarative language. They even officially started departing from Object Oriented Programming towards Data Oriented Programming ( article by their chief architect https://www.infoq.com/articles/data-oriented-programming-jav... ). Unfortunately, most of the comparison articles come from people who still code POJOs with setters, use for loops and overall rely on mutable and unsafe code.
And using Pike’s own words “go is unapologetically imperative”.
The article you link to does not contain the word "declarative". It simply states that modern Java allows more of Data-Oriented Programming, meaning a emphasis on pure data structures (records) and more expressive types (algebraic types). It doesn't say much about the code that deals with this data, which is of course procedural.