quarkusio/quarkus · error · IllegalStateException

Type {type} should be handled by the switch

Error message

Type {type} should be handled by the switch

What it means

JacksonSerializationUtils.getDefaultValue generates bytecode that yields a type's default value (0, false, etc.) when a JSON node is null. It switches over primitive type names (byte?, char, double, float, int, long, short, boolean...); any type that reaches it outside the covered set throws IllegalStateException. This is a build/deployment-time failure of Quarkus's generated Jackson serializer/deserializer machinery, i.e. an internal coverage gap rather than a documented user API.

Source

Thrown at extensions/resteasy-reactive/rest-jackson/deployment/src/main/java/io/quarkus/resteasy/reactive/jackson/deployment/processor/JacksonSerializationUtils.java:63

        // to context.readTreeAsValue() which performs proper type validation.
        return false;
    }

    static ResultHandle getDefaultValue(BytecodeCreator bytecodeCreator, Type type) {
        if (type.kind() != Kind.PRIMITIVE) {
            return bytecodeCreator.loadNull();
        }

        return switch (type.name().toString()) {
            case "byte" -> bytecodeCreator.load(DEFAULT_BYTE);
            case "boolean" -> bytecodeCreator.load(DEFAULT_BOOLEAN);
            case "char" -> bytecodeCreator.load(DEFAULT_CHAR);
            case "double" -> bytecodeCreator.load(DEFAULT_DOUBLE);
            case "float" -> bytecodeCreator.load(DEFAULT_FLOAT);
            case "int" -> bytecodeCreator.load(DEFAULT_INT);
            case "long" -> bytecodeCreator.load(DEFAULT_LONG);
            case "short" -> bytecodeCreator.load(DEFAULT_SHORT);
            default -> throw new IllegalStateException("Type " + type + " should be handled by the switch");
        };
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Change the offending field type to one supported by the switch (int, long, short, char, float, double, boolean, String, wrappers)
2. Avoid the generated code path by using standard Jackson annotations/deserializers for that DTO field
3. Check the Quarkus version and changelog; if a common primitive (e.g. byte) fails, file a Quarkus bug with a reproducer
4. Isolate the DTO and test compilation with -Dquickly to confirm which field triggers the gap

Example fix

// before
class Dto { private byte status; }

// after
class Dto { private int status; }

Set<String> supported = Set.of("char","double","float","int","long","short","boolean");
for (Field f : Dto.class.getDeclaredFields()) {
    if (f.getType().isPrimitive() && !supported.contains(f.getType().getName()))
        throw new IllegalStateException("Primitive field " + f + " lacks a generated default value");
}

static boolean isSupportedPrimitive(Class<?> c) {
    return c.isPrimitive() && !c.equals(byte.class) && !c.equals(void.class);
}

try {
    buildApplication();
} catch (IllegalStateException e) {
    if (e.getMessage() != null && e.getMessage().startsWith("Type ")) {
        // switch that DTO to standard Jackson handling
    }
}

When it happens

Trigger: A primitive-typed field whose default value must be generated is not covered by the switch (e.g. byte fields, or a new primitive path added upstream), reached while generating deserializer bytecode for a DTO class.

Common situations: DTOs with byte/byte[] or exotic primitive fields processed by the generated serializer; Quarkus upgrades exposing new paths; inconsistent switch coverage between getDefaultValue and its callers (e.g. JacksonDeserializerFactory).

Related errors

• Name cannot start with '/':${name}
• 'quarkus-narayana-lra' can only work if 'quarkus-rest-jackso
• Type {fieldType} should be handled by the switch
• Parameter type '<type>' is not supported for method '<method
• Failed to open path tree with root %s

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/2c6c518ec9019eb0. Report an issue: GitHub.