Diagnose common Clojure setup failures by reducing problems to terminal commands, checking JDK consistency, classpath construction, dependency resolution, editor REPL connection, and resource loading.
Most Clojure setup problems are not “Clojure problems”. They are JVM and classpath problems: an unexpected JDK, a dependency resolution failure, or an editor that is connected to the wrong REPL process.
resources/ issues).| Symptom | First thing to check |
|---|---|
| REPL starts from terminal but editor cannot connect | Editor command, port, working directory, and project type |
ClassNotFoundException or missing namespace |
Active classpath and namespace-to-file path mapping |
| Dependency will not resolve | Coordinates, repository access, proxy/cert settings, and cached failures |
| Tests run in IDE but not terminal | JDK, classpath aliases/tasks, and current working directory |
| Resources missing at runtime | Whether resources/ is on the same classpath used by the REPL/test command |
Debugging strategy: reduce it to the smallest reproducible command from the terminal, then add complexity back one step at a time.
This section gives you a checklist so you can get back to learning instead of fighting your environment.