quarkusio/quarkus · error · IllegalStateException

Function '${functionName}' has ${paramType} type 'Byte[]' (b

Error message

Function '${functionName}' has ${paramType} type 'Byte[]' (boxed byte array). Use 'byte[]' (primitive byte array) instead. Byte[] is not supported for binary data handling in Funqy Knative Events.

What it means

Funqy Knative Events validates function parameter and return types when binding recorders initialize. A Byte[] (boxed byte array) parameter or return type is rejected because binary CloudEvent data is handled with primitive byte[]; the boxed variant is not supported. The check throws IllegalStateException during startup.

Source

Thrown at extensions/funqy/funqy-knative-events/runtime/src/main/java/io/quarkus/funqy/runtime/bindings/knative/events/KnativeEventsBindingRecorder.java:295

        // empty set is sub-set of any set
        if (first.size() <= 0 || second.size() <= 0) {
            log.warn("Invoker " + name + " has multiple matching filters " + one + " " + two);
            return true;
        }

        boolean result = first.size() <= second.size() ? second.containsAll(first) : first.containsAll(second);
        if (result) {
            log.warn("Invoker " + name + " has multiple matching filters " + one + " " + two);
        }
        return result;
    }

    private void validateNotBoxedByteArray(Type type, String functionName, String paramType) {
        Class<?> rawType = Reflections.getRawType(type);
        if (rawType != null && rawType.isArray()) {
            Class<?> componentType = rawType.getComponentType();
            if (Byte.class.equals(componentType)) {
                throw new IllegalStateException(
                        "Function '" + functionName + "' has " + paramType + " type 'Byte[]' (boxed byte array). " +
                                "Use 'byte[]' (primitive byte array) instead. " +
                                "Byte[] is not supported for binary data handling in Funqy Knative Events.");
            }
        }
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

Change the parameter/return type from Byte[] to the primitive byte[]
If individual Byte values are needed elsewhere, convert inside the function body (ArrayUtils.toPrimitive / manual copy)
Rebuild and restart; validation runs at startup so the fix is verified immediately

Example fix

// before
@Funq public void process(byte[] ignored, Byte[] data) { ... }
// after
@Funq public void process(byte[] ignored, byte[] data) { ... }

Defensive patterns

Strategy: validation

Validate before calling

// Guard before declaring/using a Funqy knative-events function
static void ensureNotBoxedByteArray(Type type, String name) {
    Class<?> raw = Reflections.getRawType(type);
    if (raw != null && raw.isArray() && Byte.class.equals(raw.getComponentType()))
        throw new IllegalStateException(name + " must use byte[] not Byte[]");
}

Type guard

static boolean isPrimitiveByteArray(Type t) {
    Class<?> raw = Reflections.getRawType(t);
    return raw != null && raw.isArray() && raw.getComponentType() == byte.class;
}

Try / catch

try {
    invoker.validateTypes();
} catch (IllegalStateException e) {
    if (e.getMessage().contains("Byte[]")) {
        log.error("Replace Byte[] with byte[] in Funqy function signature");
    }
    throw e;
}

Prevention

Always use byte[] for binary data in Funqy functions
Enable IDE inspection for boxed array types (IntelliJ 'Array objects in calls to varargs' style inspections)
Add an ArchUnit or annotation-processor test rejecting Byte[] in @Funq signatures
Read the Funqy knative-events docs on binary CloudEvent payloads before designing signatures

When it happens

Trigger: Declaring a @Funq function whose parameter or return type is java.lang.Byte[] (e.g. void f(Byte[] data) or Byte[] f(String in)) in a project using quarkus-funqy-knative-events.

Common situations: Converting code from other frameworks where Byte[] was the convention; IDE auto-boxing when generating array types; developers confusing Byte[] with byte[] for binary payload handling.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/c11a942e650be337. Report an issue: GitHub.