Javadoc - Java API documentation

, h j shows javadoc information for a Java method or class, opening the relevant page on the Oracle website for Java.

Include Java Sources

Include the Java JDK sources when starting the REPL, to be able to navigate to the source definitions of Java methods.

Download the Java JDK sources or install via the operating system package manager, e.g. sudo apt install openjdk-17-source

Use an alias that adds the sources as an :extra-deps via a :local/root

:src/java17 alias includes the sources for Java 17 on the classpath, making them available for the Cider clj-find-var lookup.

The alias assumes the sources are located at /usr/lib/jvm/openjdk-17/lib/src.zip

clojure -M:src/java17:repl/rebel starts a rich terminal UI REPL including the Java sources on the class path.

Navigate Java Source code

, g g to run the command clj-find-var which shows

Clojure LSP hijacks the , g g key binding, so use SPC SPC clj-find-var instead.

Selecting a specific Java package (namespace) will open the Java source code in a buffer

Clojure LSP Java Sources

:source-aliases key in the Clojure LSP configuration can be used to add Java JDK sources to the Clojure LSP class path.

An alias in the project deps.edn can be used to include the Java JDK sources

{:source-paths ["src" "test" "develop"]
 :source-aliases #{":src/java17"}}

Clojure LSP currently doesn't use the user level deps.edn file, so the alias must be in the project deps.edn file.