Java extension error could not initialize class outsystems.hubedition.util.XMLutils

Java extension error could not initialize class outsystems.hubedition.util.XMLutils

  

Hi, 

I have written java extension and integrated to out systems, after that having following exception. 

could not initialize class outsystems.hubedition.util.XMLutils Java.lang.NoClassDefFoundError at outsystems.hubediton.runtimeplatform.callback.invocke.WebServiceCallbackInvocke.$vkc(unknown Source)