testcontainers/testcontainers-java · error · IllegalArgumentException

extension name must not be null or empty

Error message

extension name must not be null or empty

What it means

HiveMQExtension.Builder.build() validates that the extension's name was set before constructing the HiveMQExtension. The builder accumulates id, name, version, mainClass, etc., and refuses to build an extension with a null or empty name, since HiveMQ requires extensions to be named.

Solutions

1. Call .name("your-extension-name") on the builder before build()
2. Validate the source config/map contains a non-empty name before building
3. Add a unit test constructing the extension with all required fields

Example fix

// before
new HiveMQExtension.Builder().id("ext").version("1.0").mainClass(MyExt.class).build();
// after
new HiveMQExtension.Builder().id("ext").name("my-extension").version("1.0").mainClass(MyExt.class).build();

if (name == null || name.isEmpty()) throw new IllegalStateException("Set builder.name() before build()");

boolean hasName = builder != null && name != null && !name.isEmpty();

When it happens

Trigger: Calling HiveMQExtension.Builder.build() without calling name(...) first, or calling name(null)/name("").

Common situations: Programmatically constructing extensions where fields come from config files or maps and the 'name' key is missing or empty; copying a builder setup and dropping the name() call.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• extension main class must not be null
• extension version must not be null or empty
• Could not create DISABLED file
• Could not parse extension id from
• Extension disabling timed out after

AI-assisted analysis of testcontainers/testcontainers-java@8e549514e3 (2026-09-12). Data as JSON: /api/errors/eba1426529253e1d. Report an issue: GitHub.

Appendix: source

Thrown at modules/hivemq/src/main/java/org/testcontainers/hivemq/HiveMQExtension.java:205

        private boolean disabledOnStartup = false;

        @Nullable
        private Class<?> mainClass;

        @NotNull
        private final LinkedList<Class<?>> additionalClasses = new LinkedList<>();

        /**
         * Builds the {@link HiveMQExtension} with the provided values or default values.
         * @return the HiveMQ Extension
         */
        public @NotNull HiveMQExtension build() {
            if (id == null || id.isEmpty()) {
                throw new IllegalArgumentException("extension id must not be null or empty");
            }
            if (name == null || name.isEmpty()) {
                throw new IllegalArgumentException("extension name must not be null or empty");
            }
            if (version == null || version.isEmpty()) {
                throw new IllegalArgumentException("extension version must not be null or empty");
            }
            if (mainClass == null) {
                throw new IllegalArgumentException("extension main class must not be null");
            }
            return new HiveMQExtension(
                id,
                name,
                version,
                priority,
                startPriority,
                disabledOnStartup,
                mainClass,
                additionalClasses
            );
        }

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