apache/flink · error · InvalidTypesException

The given class is no array.

Error message

The given class is no array.

What it means

PrimitiveArrayTypeInfo.getInfoFor(Class) checks type.isArray() and throws InvalidTypesException if the class is not an array. This factory only resolves primitive arrays (int[], long[], double[], etc.). Passing a non-array class, a boxed-array (Integer[]), or a Collection is a type-dispatch error. Boxed arrays belong to BasicArrayTypeInfo; non-arrays to TypeExtractor.

Source

Thrown at flink-core/src/main/java/org/apache/flink/api/common/typeinfo/PrimitiveArrayTypeInfo.java:244

        return obj instanceof PrimitiveArrayTypeInfo;
    }

    // --------------------------------------------------------------------------------------------

    /**
     * Tries to get the PrimitiveArrayTypeInfo for an array. Returns null, if the type is an array,
     * but the component type is not a primitive type.
     *
     * @param type The class of the array.
     * @return The corresponding PrimitiveArrayTypeInfo, or null, if the array is not an array of
     *     primitives.
     * @throws InvalidTypesException Thrown, if the given class does not represent an array.
     */
    @SuppressWarnings("unchecked")
    @PublicEvolving
    public static <X> PrimitiveArrayTypeInfo<X> getInfoFor(Class<X> type) {
        if (!type.isArray()) {
            throw new InvalidTypesException("The given class is no array.");
        }

        // basic type arrays
        return (PrimitiveArrayTypeInfo<X>) TYPES.get(type);
    }

    /** Static map from array class to type info. */
    private static final Map<Class<?>, PrimitiveArrayTypeInfo<?>> TYPES = new HashMap<>();

    // initialization of the static map
    static {
        TYPES.put(boolean[].class, BOOLEAN_PRIMITIVE_ARRAY_TYPE_INFO);
        TYPES.put(byte[].class, BYTE_PRIMITIVE_ARRAY_TYPE_INFO);
        TYPES.put(short[].class, SHORT_PRIMITIVE_ARRAY_TYPE_INFO);
        TYPES.put(int[].class, INT_PRIMITIVE_ARRAY_TYPE_INFO);
        TYPES.put(long[].class, LONG_PRIMITIVE_ARRAY_TYPE_INFO);
        TYPES.put(float[].class, FLOAT_PRIMITIVE_ARRAY_TYPE_INFO);
        TYPES.put(double[].class, DOUBLE_PRIMITIVE_ARRAY_TYPE_INFO);

View on GitHub (pinned to 2f3c205e92)

Solutions

  1. Guard with type.isArray() && type.getComponentType().isPrimitive() before calling getInfoFor.
  2. For boxed arrays use BasicArrayTypeInfo.getInfoFor; for non-arrays use TypeExtractor.createTypeInfo.
  3. Prefer TypeInformation.of(TypeHint) or TypeExtractor for generic dispatch instead of calling PrimitiveArrayTypeInfo directly.

Example fix

// before
PrimitiveArrayTypeInfo.getInfoFor(Integer[].class); // boxed, not primitive array

// after
BasicArrayTypeInfo.getInfoFor(Integer[].class);
// or for true primitive arrays:
PrimitiveArrayTypeInfo.getInfoFor(int[].class);
Defensive patterns

Strategy: type-guard

Validate before calling

Class<?> c = ...;
if (!c.isArray() || !c.getComponentType().isPrimitive()) {
    throw new IllegalArgumentException(c + " is not a primitive array");
}
PrimitiveArrayTypeInfo.getInfoFor(c);

Type guard

static boolean isPrimitiveArray(Class<?> c) {
    return c.isArray() && c.getComponentType().isPrimitive();
}

Try / catch

try {
    return PrimitiveArrayTypeInfo.getInfoFor(type);
} catch (InvalidTypesException e) {
    return TypeExtractor.createTypeInfo(type);
}

Prevention

When it happens

Trigger: Calling PrimitiveArrayTypeInfo.getInfoFor with a non-array class; passing Integer[].class (boxed) instead of int[].class (primitive); routing a List or POJO through this factory by mistake.

Common situations: Custom type extractors that assume a class is a primitive array without verifying; confusion between int[] and Integer[]; generic code that picks the wrong array-type factory.

Related errors

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/995afa8c9cd7de01. Report an issue: GitHub.