apache/flink · error · InvalidTypesException

The given class is no array.

Error message

The given class is no array.

What it means

BasicArrayTypeInfo.getInfoFor(Class) checks type.isArray() and throws InvalidTypesException if the class is not an array. This factory resolves only boxed-primitive and String wrapper arrays (Boolean[], Byte[], String[], etc.) to their BasicArrayTypeInfo. Passing any non-array class (a List, a POJO, a scalar) violates the precondition.

Source

Thrown at flink-core/src/main/java/org/apache/flink/api/common/typeinfo/BasicArrayTypeInfo.java:173

    }

    @Override
    public boolean canEqual(Object obj) {
        return obj instanceof BasicArrayTypeInfo;
    }

    @Override
    public String toString() {
        return this.getClass().getSimpleName() + "<" + componentInfo + ">";
    }

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

    @SuppressWarnings("unchecked")
    @PublicEvolving
    public static <X, C> BasicArrayTypeInfo<X, C> getInfoFor(Class<X> type) {
        if (!type.isArray()) {
            throw new InvalidTypesException("The given class is no array.");
        }

        // basic type arrays
        return (BasicArrayTypeInfo<X, C>) TYPES.get(type);
    }

    private static final Map<Class<?>, BasicArrayTypeInfo<?, ?>> TYPES = new HashMap<>();

    static {
        TYPES.put(String[].class, STRING_ARRAY_TYPE_INFO);
        TYPES.put(Boolean[].class, BOOLEAN_ARRAY_TYPE_INFO);
        TYPES.put(Byte[].class, BYTE_ARRAY_TYPE_INFO);
        TYPES.put(Short[].class, SHORT_ARRAY_TYPE_INFO);
        TYPES.put(Integer[].class, INT_ARRAY_TYPE_INFO);
        TYPES.put(Long[].class, LONG_ARRAY_TYPE_INFO);
        TYPES.put(Float[].class, FLOAT_ARRAY_TYPE_INFO);
        TYPES.put(Double[].class, DOUBLE_ARRAY_TYPE_INFO);
        TYPES.put(Character[].class, CHAR_ARRAY_TYPE_INFO);

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Guard with type.isArray() before calling getInfoFor; route non-arrays to the appropriate factory (TypeExtractor, PojoTypeInfo, etc.).
2. For primitive arrays, use PrimitiveArrayTypeInfo.getInfoFor instead; for object arrays of non-basic types, use TypeExtractor.createTypeInfo.
3. Prefer the higher-level TypeInformation.of(TypeHint) or TypeExtractor.createTypeInfo, which dispatch correctly, over calling BasicArrayTypeInfo.getInfoFor directly.

Example fix

// before
BasicArrayTypeInfo.getInfoFor(MyPojo.class); // throws

// after
if (type.isArray()) {
    BasicArrayTypeInfo.getInfoFor(type);
} else {
    TypeExtractor.createTypeInfo(type);
}

Class<?> c = ...;
if (!c.isArray()) {
    throw new IllegalArgumentException(c + " is not an array");
}
BasicArrayTypeInfo.getInfoFor(c);

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

// Prefer dispatch via TypeExtractor rather than catching
try {
    return BasicArrayTypeInfo.getInfoFor(type);
} catch (InvalidTypesException e) {
    return TypeExtractor.createTypeInfo(type);
}

When it happens

Trigger: Calling BasicArrayTypeInfo.getInfoFor(someClass) where someClass is a Collection, a POJO, or a scalar; reflection-driven code that routes arbitrary classes through this factory without first checking isArray().

Common situations: Custom type-info builders that dispatch to BasicArrayTypeInfo without an isArray guard; serializing a field typed as List<T> or T (erased) and landing on this factory; misclassifying a POJO array vs. a basic array.

Related errors

• The given class is no array.
• Tuple type expected but was: {}
• Return type {keyType} of KeySelector {keyExtractor.getClass(
• Class is not a TypeInfoFactory.
• Could not create the type information for '{}'. The most com

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/543132640c9061da. Report an issue: GitHub.