flowable/flowable-engine · error · FlowableException

Error instantiating XML importer '%s' for type '%s'

Error message

Error instantiating XML importer '%s' for type '%s'

What it means

Flowable's DefaultXMLImporterFactory creates the WSDL/XML importer for BPMN import elements via reflection, hardcoding 'org.flowable.engine.impl.webservice.CxfWSDLImporter' and loading it through the current thread's context ClassLoader. The message is thrown when the class is found but cannot be instantiated (e.g. missing CXF dependencies, no no-arg constructor, linkage or access errors) while deploying a process that uses <import> / web service tasks. It wraps the reflective failure in a FlowableException with the importer class name and the BPMN import type.

Source

Thrown at modules/flowable-engine/src/main/java/org/flowable/engine/impl/bpmn/parser/factory/DefaultXMLImporterFactory.java:41

 * 
 * @author Christophe DENEUX
 */
public class DefaultXMLImporterFactory implements XMLImporterFactory {

    // Name of the default XML Importer, provided by flowable-cxf
    private static final String DEFAULT_XML_IMPORTER_FACTORY_CLASSNAME = "org.flowable.engine.impl.webservice.CxfWSDLImporter";

    @Override
    public XMLImporter createXMLImporter(Import theImport) throws FlowableException {

        try {
            Class<?> wsdlImporterClass = Class.forName(DEFAULT_XML_IMPORTER_FACTORY_CLASSNAME, true,
                    Thread.currentThread().getContextClassLoader());
            return (XMLImporter) wsdlImporterClass.getConstructor().newInstance();
        } catch (ClassNotFoundException e) {
            throw new FlowableException("Could not find importer class for type " + theImport.getImportType(), e);
        } catch (Exception e) {
            throw new FlowableException(String.format("Error instantiating XML importer '%s' for type '%s'",
                    DEFAULT_XML_IMPORTER_FACTORY_CLASSNAME, theImport.getImportType()), e);
        }
    }
}

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Add the Flowable web-service/CXF dependencies (e.g. org.flowable:flowable-cxf plus Apache CXF artifacts) to the application classpath
2. If no web service import is intended, remove the <import> declaration and related service tasks from the BPMN XML
3. Ensure Thread.currentThread().getContextClassLoader() can see the class (set the context ClassLoader appropriately in your launch environment)
4. Inspect the wrapped cause ('Caused by') of the FlowableException to distinguish missing classes from constructor/access problems

Example fix

// before (pom.xml)
<dependency>
  <groupId>org.flowable</groupId>
  <artifactId>flowable-engine</artifactId>
</dependency>

// after
<dependency>
  <groupId>org.flowable</groupId>
  <artifactId>flowable-engine</artifactId>
</dependency>
<dependency>
  <groupId>org.flowable</groupId>
  <artifactId>flowable-cxf</artifactId>
</dependency>

// before deployment
String cls = "org.flowable.engine.impl.webservice.CxfWSDLImporter";
try {
  Class.forName(cls, true, Thread.currentThread().getContextClassLoader());
} catch (Throwable t) {
  throw new IllegalStateException("WSDL importer missing on classpath: add flowable-cxf + CXF dependencies", t);
}

boolean canInstantiateWsdlImporter() {
  try {
    Class<?> c = Class.forName("org.flowable.engine.impl.webservice.CxfWSDLImporter",
        true, Thread.currentThread().getContextClassLoader());
    c.getConstructor();
    return true;
  } catch (Throwable t) {
    return false;
  }
}

try {
  repositoryService.createDeployment().addInputStream(...).deploy();
} catch (FlowableException e) {
  if (e.getMessage() != null && e.getMessage().startsWith("Error instantiating XML importer")) {
    logger.error("CXF/WSDL support missing or broken; check flowable-cxf dependency and classloader", e);
  } else {
    throw e;
  }
}

When it happens

Trigger: Deploying a BPMN XML containing an <import type="..."> element (web service import); the reflection call wsdlImporterClass.getConstructor().newInstance() fails with an exception other than ClassNotFoundException — typically NoClassDefFoundError/LinkageError because CXF classes (cxf-rt-frontend-jaxws etc.) are not on the classpath, or InstantiationException/IllegalAccessException.

Common situations: Using the Flowable web-service (WSDL) integration without adding the flowable-cxf/CXF Maven dependencies; running in a container (Spring Boot fat jar, OSGi, app server) where the thread context ClassLoader cannot see the CxfWSDLImporter class; upgrading Flowable versions where the webservice module or package layout changed.

Related errors

• Could not get context class loader
• BPMN XSD could not be found
• The bpmn 2.0 xml is not properly encoded
• The ${task} cannot be deleted because is part of a running p
• TypeConverter ${clazz} could not be instantiated

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/30f780399374e64b. Report an issue: GitHub.