quarkusio/quarkus · error · IllegalArgumentException

Target directory already exists: ${path}

Error message

Target directory already exists: ${path}

What it means

checkProjectRootPath computes outputPath/name and refuses to proceed if that directory already exists, to avoid overwriting an existing project. It throws an IllegalArgumentException containing the absolute target directory path.

Source

Thrown at independent-projects/tools/devtools-common/src/main/java/io/quarkus/devtools/commands/CreateProjectHelper.java:150

            throw new IllegalArgumentException(name + " is not a valid class name");
        }
        return name;
    }

    public static String checkPackageName(String name) {
        if (!SourceVersion.isName(name)) { // checks for valid identifiers & use of keywords
            throw new IllegalArgumentException(name + " is not a valid package name");
        }
        return name;
    }

    public static Path checkProjectRootPath(Path outputPath, String name) {
        requireNonNull(name, "Must specify project name");
        requireNonNull(outputPath, "Must specify output path");

        Path projectRootPath = outputPath.resolve(name);
        if (projectRootPath.toFile().exists()) {
            throw new IllegalArgumentException(
                    "Target directory already exists: " + projectRootPath.toAbsolutePath().toString());
        }
        return projectRootPath;
    }

    public static Path createOutputDirectory(String targetDirectory) {
        Path origin = new File(System.getProperty("user.dir")).toPath();
        Path outputPath = (targetDirectory == null ? origin : origin.resolve(targetDirectory));
        try {
            Files.createDirectories(outputPath);
        } catch (IOException e) {
            throw new IllegalArgumentException("Could not create directory " + targetDirectory, e);
        }
        return outputPath;
    }

    public static Set<String> sanitizeExtensions(Set<String> extensions) {
        if (extensions == null) {

View on GitHub (pinned to e1c734241f)

Solutions

1. Choose a different project name or output directory
2. Delete or move the existing target directory before re-running
3. Point outputPath at an empty location
4. If overwrite is truly intended, remove the directory explicitly: rm -rf <dir>

Example fix

// before
createProject.outputDirectory(Path.of(".")); createProject.name("my-app"); // ./my-app exists
// after
rm -rf ./my-app  // or use name("my-app-v2")

Path root = outputPath.resolve(name);
if (root.toFile().exists()) { throw new IllegalArgumentException("choose another name/output or remove " + root.toAbsolutePath()); }

try { helper.checkProjectRootPath(outputPath, name); } catch (IllegalArgumentException e) { if (e.getMessage().startsWith("Target directory already exists")) { useAlternateDirOrAbort(); } }

When it happens

Trigger: Calling CreateProject (or checkProjectRootPath directly) where outputPath.resolve(name) already exists on disk — e.g. re-running generation into the same output directory with the same project name.

Common situations: Re-running a failed/interrupted generation after some files were created; scaffolding into a directory that already holds another project; running the same script twice without cleaning output.

Related errors

• The version 2 CLI can not be used with Quarkus 1.x projects.
• Could not create directory ${outputDirectory}
• Failed to create the project directory: + targetDirectory
• Project path needs to point to a directory: + targetDirector
• You can't create a project when the directory is not empty:

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/b0dbd6290307d0b8. Report an issue: GitHub.