Reading process variable (Custom Java object) from a spring application through RestAPI not working

I have a SpringBoot application using embedded tomcat which has a Delegate method that is adding a process variable. Code snippet as below:
File xmlFile = new File(“XXXXXXXXXX.xml”);
OrderRequest orderReq = null;

	  JAXBContext jaxbContext;
	  try
	  {
	      jaxbContext = JAXBContext.newInstance(OrderRequest.class);             
	   
	      Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
	     
	      orderReq = (OrderRequest) jaxbUnmarshaller.unmarshal(xmlFile);
	       
	      System.out.println(orderReq);
	  }
	  catch (JAXBException e)
	  {
	      e.printStackTrace();
	  }

ObjectValue typedOrderReqValue = Variables.objectValue(orderReq).serializationDataFormat(SerializationDataFormats.XML).create();

	  execution.setVariable("ORDER-REQ", typedOrderReqValue);

execution.setVariable(“ORDER-REQ”, typedOrderReqValue);

This is resulting in below exception -
org.camunda.bpm.engine.ProcessEngineException: Cannot serialize object in variable ‘ORDER-REQ’: SPIN/DOM-XML-01030 Cannot create context
at org.camunda.bpm.engine.impl.variable.serializer.AbstractSerializableValueSerializer.writeValue(AbstractSerializableValueSerializer.java:57) ~[camunda-engine-7.11.0.jar:7.11.0]
at org.camunda.bpm.engine.impl.variable.serializer.AbstractSerializableValueSerializer.writeValue(AbstractSerializableValueSerializer.java:31) ~[camunda-engine-7.11.0.jar:7.11.0]
at org.camunda.bpm.engine.impl.persistence.entity.util.TypedValueField.writeValue(TypedValueField.java:163) ~[camunda-engine-7.11.0.jar:7.11.0]
at org.camunda.bpm.engine.impl.persistence.entity.util.TypedValueField.setValue(TypedValueField.java:123) ~[camunda-engine-7.11.0.jar:7.11.0]
at org.camunda.bpm.engine.impl.persistence.entity.VariableInstanceEntity.(VariableInstanceEntity.java:127) ~[camunda-engine-7.11.0.jar:7.11.0]
at org.camunda.bpm.engine.impl.persistence.entity.VariableInstanceEntity.create(VariableInstanceEntity.java:146) ~[camunda-engine-7.11.0.jar:7.11.0]

Could you please tell how to resolve this. This works when I try to set this process variable from a standalone application deployed in tomcat.