skylot/jadx · error · JadxRuntimeException

Unexpected field type class:

Error message

Unexpected field type class: 

What it means

Thrown by AnnotationGen.encodeValue() when processing an ENCODED_ENUM or ENCODED_FIELD annotation value whose backing object is neither an IFieldRef nor a FieldInfo. These are the only two expected types for static field references in annotation values; any other type indicates an internal inconsistency in how the annotation was parsed from the DEX.

Source

Thrown at jadx-core/src/main/java/jadx/core/codegen/AnnotationGen.java:196

				code.add(StringUtils.formatDouble((Double) value));
				break;
			case ENCODED_STRING:
				code.add(stringUtils.unescapeString((String) value));
				break;
			case ENCODED_TYPE:
				classGen.useType(code, ArgType.parse((String) value));
				code.add(".class");
				break;
			case ENCODED_ENUM:
			case ENCODED_FIELD:
				// must be a static field
				if (value instanceof IFieldRef) {
					FieldInfo fieldInfo = FieldInfo.fromRef(root, (IFieldRef) value);
					InsnGen.makeStaticFieldAccess(code, fieldInfo, classGen);
				} else if (value instanceof FieldInfo) {
					InsnGen.makeStaticFieldAccess(code, (FieldInfo) value, classGen);
				} else {
					throw new JadxRuntimeException("Unexpected field type class: " + value.getClass());
				}
				break;
			case ENCODED_METHOD:
				// TODO
				break;
			case ENCODED_ARRAY:
				code.add('{');
				Iterator<?> it = ((Iterable<?>) value).iterator();
				while (it.hasNext()) {
					EncodedValue v = (EncodedValue) it.next();
					encodeValue(cls.root(), code, v);
					if (it.hasNext()) {
						code.add(", ");
					}
				}
				code.add('}');
				break;
			case ENCODED_ANNOTATION:

View on GitHub (pinned to e738a26571)

Solutions

1. Report the APK/APK file as a test case to the jadx project — this is likely an internal jadx bug in annotation processing.
2. Update to the latest jadx version where the annotation value handling may have been fixed.
3. As a workaround, exclude the affected class from decompilation or use --no-debug-info / fallback mode.

try {
    annotationGen.encodeValue(root, code, encodedValue);
} catch (JadxRuntimeException e) {
    if (e.getMessage().startsWith("Unexpected field type class")) {
        // Fallback: emit a comment with the raw value instead of failing
        code.add("/* unexpected annotation field value: " + value + " */");
        logger.warn("Skipping annotation field with unexpected type", e);
    } else {
        throw e;
    }
}

When it happens

Trigger: Decompiling a DEX/APK where an annotation references a field (enum constant or static field) and the value object produced by the dex parser is an unexpected type. This usually indicates a bug in the annotation attribute processing pipeline or a malformed DEX.

Common situations: Obfuscated or modified APKs with non-standard annotation structures. A jadx version regression in annotation parsing that produces a different value wrapper type than expected.

Related errors

• Can't decode value:
• Unknown output format
• Unknown condition mode:
• Unknown arg type
• Unknown instruction:

AI-assisted analysis of skylot/jadx@e738a26571 (2026-08-14). Data as JSON: /api/errors/e4623e2de198556a. Report an issue: GitHub.