quarkusio/quarkus · error · MojoExecutionException

Either the `extension` or `extensions` parameter must be set

Error message

Either the `extension` or `extensions` parameter must be set

What it means

This MojoExecutionException is thrown by RemoveExtensionMojo.validateParameters when the quarkus:remove-extension goal receives neither or both of the mutually exclusive extension parameters: single `extension` and list `extensions`. Exactly one must be provided; the goal refuses to guess the user's intent.

Source

Thrown at devtools/maven/src/main/java/io/quarkus/maven/RemoveExtensionMojo.java:43

public class RemoveExtensionMojo extends QuarkusProjectMojoBase {

    /**
     * The list of extensions to be removed.
     */
    @Parameter(property = "extensions")
    Set<String> extensions;

    /**
     * For usability reason, this parameter allows removing a single extension.
     */
    @Parameter(property = "extension")
    String extension;

    @Override
    protected void validateParameters() throws MojoExecutionException {
        if ((StringUtils.isBlank(extension) && (extensions == null || extensions.isEmpty())) // None are set
                || (!StringUtils.isBlank(extension) && extensions != null && !extensions.isEmpty())) { // Both are set
            throw new MojoExecutionException("Either the `extension` or `extensions` parameter must be set");
        }
    }

    @Override
    public void doExecute(final QuarkusProject quarkusProject, final MessageWriter log) throws MojoExecutionException {

        Set<String> ext = new HashSet<>();
        if (extensions != null && !extensions.isEmpty()) {
            ext.addAll(extensions);
        } else {
            // Parse the "extension" just in case it contains several comma-separated values
            // https://github.com/quarkusio/quarkus/issues/2393
            ext.addAll(Arrays.stream(extension.split(",")).map(s -> s.trim()).collect(Collectors.toSet()));
        }

        try {
            final QuarkusCommandOutcome outcome = new RemoveExtensions(quarkusProject)
                    .extensions(ext.stream().map(String::trim).collect(Collectors.toSet()))

View on GitHub (pinned to e1c734241f)

Solutions

1. Provide exactly one parameter: -Dextensions="rest,jackson" for multiple, or -Dextension="rest" for a single extension
2. Remove the conflicting duplicate flag from the command line or .mvn/maven.config/CI defaults
3. Configure the extension(s) in the plugin <configuration> block instead of mixing both properties

Example fix

// before
mvn quarkus:remove-extension -Dextension="rest" -Dextensions="rest,jackson"
// after
mvn quarkus:remove-extension -Dextensions="rest,jackson"

String extension = System.getProperty("extension");
String extensions = System.getProperty("extensions");
boolean noneSet = (extension == null || extension.isBlank()) && (extensions == null || extensions.isBlank());
boolean bothSet = extension != null && !extension.isBlank() && extensions != null && !extensions.isBlank();
if (noneSet || bothSet) {
    throw new IllegalArgumentException("Set exactly one of -Dextension or -Dextensions");
}

When it happens

Trigger: Running mvn quarkus:remove-extension with no -Dextension/-Dextensions, or supplying both -Dextension="rest" and -Dextensions="rest,jackson" in the same invocation.

Common situations: Copy-pasting commands with leftover flags; CI scripts setting defaults in .mvn/maven.config that collide with explicit CLI args; forgetting the argument entirely.

Related errors

• Either the `extension` or `extensions` parameter must be set
• This goal requires a project
• This goal requires a Quarkus extension registry client to be
• Unable to determine groupId and artifactId of the jar that c
• Unable to determine groupId and artifactId of the extension

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/0d3d5519cd8f9bec. Report an issue: GitHub.