quarkusio/quarkus · error · MojoExecutionException

Hot reloadable dependency <moduleId> has not been compiled y

Error message

Hot reloadable dependency <moduleId> has not been compiled yet (the classes directory <classesDir> does not exist)

What it means

For a hot-reloadable local dependency that declares source or resource paths but whose target/classes directory does not exist, DevMojo refuses to proceed: the module must be compiled before dev mode can watch and hot-reload it. It throws MojoExecutionException naming the module id and the missing classes directory.

Source

Thrown at devtools/maven/src/main/java/io/quarkus/maven/DevMojo.java:1294

            final BuildBase build = profile.getBuild();
            if (build != null) {
                resourcePaths.addAll(
                        build.getResources().stream()
                                .map(Resource::getDirectory)
                                .map(Path::of)
                                .map(Path::toAbsolutePath)
                                .collect(Collectors.toList()));
                testResourcePaths.addAll(
                        build.getTestResources().stream()
                                .map(Resource::getDirectory)
                                .map(Path::of)
                                .map(Path::toAbsolutePath)
                                .collect(Collectors.toList()));
            }
        }

        if (classesPath == null && (!sourcePaths.isEmpty() || !resourcePaths.isEmpty())) {
            throw new MojoExecutionException("Hot reloadable dependency " + module.getWorkspaceModule().getId()
                    + " has not been compiled yet (the classes directory " + (classesDir == null ? "" : classesDir)
                    + " does not exist)");
        }

        Path targetDir = Path.of(project.getBuild().getDirectory());

        // In some cases, we may have a generatedSourcesPath that has not been created, or that has been deleted
        // after Maven created it. Javac will not be happy about it, and we will mimic Maven and auto-create it
        // when this happens, to avoid crashing the compiler
        if (generatedSourcesPath != null && Files.notExists(Path.of(generatedSourcesPath))) {
            Files.createDirectories(Path.of(generatedSourcesPath));
        }

        DevModeContext.ModuleInfo moduleInfo = new DevModeContext.ModuleInfo.Builder()
                .setArtifactKey(module.getKey())
                .setProjectDirectory(projectDirectory)
                .setSourcePaths(PathList.from(sourcePaths))
                .setClassesPath(classesPath)

View on GitHub (pinned to e1c734241f)

Solutions

1. Compile the workspace first: run `mvn install -DskipTests` from the multi-module root before `mvn quarkus:dev`.
2. If a `mvn clean` was performed, rebuild the affected module.
3. Launch dev mode from the application module with the reactor (root) build so sibling modules are compiled.
4. Verify the classes directory path shown in the message exists after building the module.

Example fix

// before
cd my-app && mvn quarkus:dev   # sibling lib module never built
// after
mvn install -DskipTests && cd my-app && mvn quarkus:dev

// verify each workspace dependency has been compiled before dev mode
Path classesDir = Path.of("../my-lib/target/classes");
if (Files.isDirectory(Path.of("../my-lib/src/main/java")) && !Files.isDirectory(classesDir)) {
    throw new IllegalStateException("Module not compiled: " + classesDir);
}

When it happens

Trigger: Running quarkus:dev in a multi-module project where a workspace sibling module has sources/resources registered but has never been compiled, so its classes directory is absent while sourcePaths/resourcePaths are non-empty.

Common situations: Fresh clone without an initial `mvn install`; dependency module cleaned (`mvn clean`) just before launching dev mode; IDE deleting output directories; dev mode started from a submodule without building the reactor first.

Related errors

• Local dependency <module> does not appear to have any source
• Dev mode process did not complete successfully
• Failed to run
• Failed to obtain descriptor for Maven plugin <pluginId> goal
• Top-level project base directory <dir> specified with system

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/e88e5c07112a876d. Report an issue: GitHub.