skylot/jadx · error · JadxRuntimeException

Error decode class: {}

Error message

Error decode class: {}

What it means

ClassNode.load() wraps its entire class-loading body (fields, methods, attributes, static values, cache build) in a try/catch. ANY exception during class decode is re-thrown as JadxRuntimeException with the class info. This is a fatal-per-class error: the whole ClassNode fails to construct.

Source

Thrown at jadx-core/src/main/java/jadx/core/dex/nodes/ClassNode.java:144

			ListConsumer<IFieldData, FieldNode> fieldsConsumer = new ListConsumer<>(fld -> FieldNode.build(this, fld));
			ListConsumer<IMethodData, MethodNode> methodsConsumer = new ListConsumer<>(mth -> MethodNode.build(this, mth));
			cls.visitFieldsAndMethods(fieldsConsumer, methodsConsumer);
			this.fields = fieldsConsumer.getResult();
			this.methods = methodsConsumer.getResult();
			if (reloading) {
				restoreUsageData();
			}
			initStaticValues(fields);
			processAttributes(this);
			processSpecialClasses(this);
			buildCache();

			// TODO: implement module attribute parsing
			if (this.accessFlags.isModuleInfo()) {
				this.addWarnComment("Modules not supported yet");
			}
		} catch (Exception e) {
			throw new JadxRuntimeException("Error decode class: " + clsInfo, e);
		}
	}

	private void restoreUsageData() {
		IUsageInfoData usageInfoData = root.getArgs().getUsageInfoCache().get(root);
		if (usageInfoData != null) {
			usageInfoData.applyForClass(this);
		} else {
			LOG.warn("Can't restore usage data for class: {}", this);
		}
	}

	private ArgType checkSuperType(IClassData cls) {
		String superType = cls.getSuperType();
		if (superType == null) {
			if (clsInfo.getType().getObject().equals(Consts.CLASS_OBJECT)) {
				// java.lang.Object don't have super class
				return null;

View on GitHub (pinned to e738a26571)

Solutions

1. Upgrade JADX.
2. Decompile class-by-class to isolate which class triggers the error.
3. Use --show-bad-code and decompile the rest of the APK excluding the failing class.
4. Report the class name and full nested stack trace (the cause is chained) upstream.

// When scripting, isolate class decode so one bad class does not abort the batch.
for (JavaClass cls : jadx.getClasses()) {
    try {
        String code = cls.getCode();
        results.put(cls.getFullName(), code);
    } catch (JadxRuntimeException e) {
        log.error("Class decode failed: {}", cls.getFullName(), e);
        results.put(cls.getFullName(), "// DECODE FAILED: " + e.getMessage());
    }
}

When it happens

Trigger: An exception anywhere in class loading — field/method node construction, attribute processing, static value initialization, or special-class detection (enums, annotations, records).

Common situations: Corrupt class data, missing cross-class references, unsupported attributes, malformed signatures, or an upstream error in any sub-parser. The blast radius is the entire class.

Related errors

• Failed to decode insn: {}
• Unknown instruction: '{}'
• Failed to load method reference for insn: {}
• Failed to get call site for insn: {}
• 'invoke-custom' instruction processing error: {}

AI-assisted analysis of skylot/jadx@e738a26571 (2026-08-14). Data as JSON: /api/errors/976e0e0b1b859559. Report an issue: GitHub.