Does the problem happens to you always? Or just sometimes? If it happens again please could you take few thread dumps (http://wiki.netbeans.org/GenerateThreadDump) over the period of 30 seconds and attach them here. Without that I cannot resolve this issue. Thanks.

I also assume there was no exception in IDE log, right? (View -> IDE Log)

Yes, it happens every time at this version of NB. But this is also the first time I try to use it on Mac.

There are exceptions every time, some class not found that seems should in JDK or JRE. Maybe this feature need higher version of JDK?

SEVERE [org.openide.util.RequestProcessor]: Error in RequestProcessor org.netbeans.modules.websvc.saas.ui.wizards.AddWebServiceDlg$4
java.lang.NoClassDefFoundError: Could not initialize class com.sun.xml.bind.DatatypeConverterImpl
	at com.sun.xml.bind.v2.model.impl.RuntimeBuiltinLeafInfoImpl$13.parse(RuntimeBuiltinLeafInfoImpl.java:677)
	at com.sun.xml.bind.v2.model.impl.RuntimeBuiltinLeafInfoImpl$13.parse(RuntimeBuiltinLeafInfoImpl.java:675)
	at com.sun.xml.bind.v2.runtime.reflect.TransducedAccessor$CompositeTransducedAccessorImpl.parse(TransducedAccessor.java:247)
	at com.sun.xml.bind.v2.runtime.unmarshaller.StructureLoader.startElement(StructureLoader.java:210)
	at com.sun.xml.bind.v2.runtime.unmarshaller.ProxyLoader.startElement(ProxyLoader.java:60)
	at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:501)
	at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:480)
	at com.sun.xml.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:150)
	at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:501)
	at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:179)
	at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:377)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2756)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:647)
	at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
	at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
	at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
	at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
	at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
	at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
	at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:218)
	at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:190)
	at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:172)
	at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:219)
	at org.netbeans.modules.websvc.saas.util.SaasUtil.loadJaxbObject(SaasUtil.java:190)
	at org.netbeans.modules.websvc.saas.util.SaasUtil$InputStreamJaxbReader.loadJaxbObject(SaasUtil.java:855)
	at org.netbeans.modules.websvc.saas.util.SaasUtil.loadJaxbObject(SaasUtil.java:135)
	at org.netbeans.modules.websvc.saas.util.SaasUtil.loadJaxbObject(SaasUtil.java:121)
	at org.netbeans.modules.websvc.saas.util.SaasUtil.loadSaasServices(SaasUtil.java:318)
	at org.netbeans.modules.websvc.saas.model.SaasServicesModel.loadSaasServiceFile(SaasServicesModel.java:208)
	at org.netbeans.modules.websvc.saas.model.SaasServicesModel.loadFromDefaultFileSystem(SaasServicesModel.java:146)
	at org.netbeans.modules.websvc.saas.model.SaasServicesModel.initRootGroup(SaasServicesModel.java:110)
	at org.netbeans.modules.websvc.saas.ui.wizards.AddWebServiceDlg$4.run(AddWebServiceDlg.java:427)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2044)

My env:

Product Version: NetBeans IDE 7.3 (Build 201302132200)
Java: 1.6.0_45; Java HotSpot(TM) 64-Bit Server VM 20.45-b01-451
Runtime: Java(TM) SE Runtime Environment 1.6.0_45-b06-451-11M4406
System: Mac OS X version 10.7.5 running on x86_64; MacRoman; en_US (nb)

I think there are two problems here:

#1) there is something wrong with XML parser in your Mac OS JDK. I have no idea what. Could you try different JDK? 7? PetrJ, you are Mac user, what JDK do you use? Have you ever seen this type of error? 

#2) when XML parsing fails with NoClassDefFoundError the Services node does not handle it well as it was catching just Exception. I'm fixing that and catching Throwable now: web-main#0ec5699c3492 . That should remove "Loading..." node after loading is finished. But if XML parser does not work then likely no web services will be shown.

I think this must be a specific issue of your setup as I have not heard this complaint before and there are many Mac users of the IDE.

> there is something wrong with XML parser in your Mac OS JDK. I have no idea
> what. Could you try different JDK? 7? PetrJ, you are Mac user, what JDK do you
> use? Have you ever seen this type of error? 

I am trying this out with pretty much the same environment (JDK 6, Mac OS X 10.7.5), and I can not reproduce the problem. The "Loading..." node appears, but after a while it completes and shows web services (it takes some time though, close to 10 seconds).

gooddreams, can you please try this out with the latest JDK 7, to see if it also happens there? Thanks.

XML Parser problems like this one used to be caused (10 years ago) by having parser jars directly in JDK endorsed directory or something like that.

Looks like specific problem of your workstation.

Please try different JDK. Thanks.

Integrated into 'main-golden', will be available in build *201305232300* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)
Changeset: http://hg.netbeans.org/main-golden/rev/0ec5699c3492
User: David Konecny <dkonecny@netbeans.org>
Log: #229759 - handle NoClassDefFoundError exception better

(In reply to comment #5)
> > there is something wrong with XML parser in your Mac OS JDK. I have no idea
> > what. Could you try different JDK? 7? PetrJ, you are Mac user, what JDK do you
> > use? Have you ever seen this type of error? 
> 
> I am trying this out with pretty much the same environment (JDK 6, Mac OS X
> 10.7.5), and I can not reproduce the problem. The "Loading..." node appears,
> but after a while it completes and shows web services (it takes some time
> though, close to 10 seconds).
> 
> gooddreams, can you please try this out with the latest JDK 7, to see if it
> also happens there? Thanks.

I have downloaded new jdk 7 (previously I use jdk 6) and configure NetBeans to use it (etc/netbeans.conf). But still have the problem. Don't know why not works on my Mac Pro.