web services - What is the reason of java.lang.reflect.InvocationTargetException when calling a SOAP WS? -

i tryig understand soap ws. write simple classes follow. when deploy application in glassfish , test it, server returns java.lang.reflect.invocationtargetexception. can problem is?

@webservice public class authorws { authorservice authorservice = new authorservice();  @webmethod public author getauthorbyid(int authorid) {     return authorservice.getauthorbyid(authorid); }  @webmethod public arraylist<author> getallauthors() {     return authorservice.getallauthors(); } } 

service class:

public class authorservice { authordao authordao = new authordao(); public author getauthorbyid(int authorid){      return authordao.getauthorbyid(authorid); } public arraylist<author> getallauthors(){     return authordao.getallauthors(); } } 

dao class:

public class authordao {  public author getauthorbyid(int authorid){     sessionfactory sessionfactory = new configuration().configure().buildsessionfactory();     criteria criteria = sessionfactory.opensession().createcriteria(author.class);     criteria.add(restrictions.eq("authorid", authorid));     return (author) criteria.uniqueresult();  } public arraylist<author> getallauthors(){     sessionfactory sessionfactory = new configuration().configure().buildsessionfactory();     criteria criteria = sessionfactory.opensession().createcriteria(author.class);     return (arraylist<author>) criteria.list(); } 

exception:

'caused by: java.lang.reflect.invocationtargetexception @ sun.reflect.nativemethodaccessorimpl.invoke0(native method) @ sun.reflect.nativemethodaccessorimpl.invoke(nativemethodaccessorimpl.java:62) @ sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:43) @ java.lang.reflect.method.invoke(method.java:483) @ org.glassfish.webservices.monitoring.webservicetesterservlet.dopost(webservicetesterservlet.java:313) ... 32 more caused by: com.sun.xml.ws.fault.serversoapfaultexception: client received soap fault server: com.sun.enterprise.container.common.spi.util.injectionexception: error creating managed object class: class com.hojat.librarysoapws.ws.authorws please see server log find more detail regarding exact cause of failure. @ com.sun.xml.ws.fault.soap11fault.getprotocolexception(soap11fault.java:193) @ com.sun.xml.ws.fault.soapfaultbuilder.createexception(soapfaultbuilder.java:131) @ com.sun.xml.ws.client.sei.stubhandler.readresponse(stubhandler.java:253) @ com.sun.xml.ws.db.databindingimpl.deserializeresponse(databindingimpl.java:203) @ com.sun.xml.ws.db.databindingimpl.deserializeresponse(databindingimpl.java:290) @ com.sun.xml.ws.client.sei.syncmethodhandler.invoke(syncmethodhandler.java:119) @ com.sun.xml.ws.client.sei.syncmethodhandler.invoke(syncmethodhandler.java:92) @ com.sun.xml.ws.client.sei.seistub.invoke(seistub.java:161) @ com.sun.proxy.$proxy312.getallauthors(unknown source)'

the problem on server side, can see stack trace

: client received soap fault server:  com.sun.enterprise.container.common.spi.util.injectionexception:  error creating managed object class:  class com.hojat.librarysoapws.ws.authorws  please see server log find more detail regarding exact cause of failure. 

so check server log.