I was struggling recently with getting Java code completion to work in Clojure with interlop. After investigating I found that clojure-lsp has no java dot completion interlop! Only CIDER does.

(clojure +lsp)      ; lsp does not fully support java interlop
(clojure)           ; use this and use "cider-jack-in"
            

To fix this, disable the +lsp flag init.el for clojure, and only use "cider-jack-in" for auto completion.

First type the object name in, and put your cursor on the '.'. Company should then display all available methods for the initaited java object.

(. file-object)
            

It also has autocomplete for threading macros. Going over '.' will also show autocomplete.

(-> file-object .)