SynchronizePomAction is registered for all XML file causing Eclipse to hang on when a doctype is declared.

Why are the pom actions associated to "*.xml" files ?:
<objectContribution objectClass="org.eclipse.core.resources.IFile" nameFilter="project.xml" id="maven.plugin.xml.contribution.ifile">

You should filter on "project.xml", at least untill you fixed the selecetionChanged method not to block if the XML file has a doctype reference and the computer has no connection to the internet :
Oct 14, 2005 8:14:58 AM org.mevenide.ui.eclipse.actions.SynchronizePomAction selectionChanged
SEVERE: Unable to read project file
java.net.ConnectException: Connection timed out
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.Socket.connect(Socket.java:507)
at java.net.Socket.connect(Socket.java:457)
at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:365)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:477)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:214)
at sun.net.www.http.HttpClient.New(HttpClient.java:287)
at sun.net.www.http.HttpClient.New(HttpClient.java:299)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:792)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:744)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:669)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:913)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(XMLEntityManager.java:973)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startEntity(XMLEntityManager.java:905)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startDTDEntity(XMLEntityManager.java:872)
at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.setInputSource(XMLDTDScannerImpl.java:282)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDispatcher.dispatch(XMLDocumentScannerImpl.java:1021)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:368)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:834)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:148)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1242)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:453)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:810)
at org.jdom.input.SAXBuilder.build(SAXBuilder.java:789)
at org.mevenide.context.JDomProjectUnmarshaller.parseRootElement(JDomProjectUnmarshaller.java:86)
at org.mevenide.context.JDomProjectUnmarshaller.parse(JDomProjectUnmarshaller.java:72)
at org.mevenide.project.io.ProjectReader.read(ProjectReader.java:75)
at org.mevenide.ui.eclipse.actions.SynchronizePomAction.selectionChanged(SynchronizePomAction.java:64)
at org.eclipse.ui.internal.PluginAction.refreshEnablement(PluginAction.java:200)
at org.eclipse.ui.internal.PluginAction.selectionChanged(PluginAction.java:271)
at org.eclipse.ui.internal.ObjectActionContributor.contributeObjectActions(ObjectActionContributor.java:138)
at org.eclipse.ui.internal.ObjectActionContributorManager.contributeObjectActions(ObjectActionContributorManager.java:137)
at org.eclipse.ui.internal.PopupMenuExtender.addObjectActions(PopupMenuExtender.java:246)
at org.eclipse.ui.internal.PopupMenuExtender.menuAboutToShow(PopupMenuExtender.java:273)
at org.eclipse.jface.action.MenuManager.fireAboutToShow(MenuManager.java:285)
at org.eclipse.jface.action.MenuManager.handleAboutToShow(MenuManager.java:372)
at org.eclipse.jface.action.MenuManager.access$0(MenuManager.java:369)
at org.eclipse.jface.action.MenuManager$2.menuShown(MenuManager.java:386)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:117)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1021)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1045)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1026)
at org.eclipse.swt.widgets.Menu._setVisible(Menu.java:175)
at org.eclipse.swt.widgets.Display.runPopups(Display.java:2893)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2569)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1699)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1663)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:367)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:143)
at org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:103)
at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:226)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:376)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:163)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.eclipse.core.launcher.Main.invokeFramework(Main.java:334)
at org.eclipse.core.launcher.Main.basicRun(Main.java:278)
at org.eclipse.core.launcher.Main.run(Main.java:973)
at org.eclipse.core.launcher.Main.main(Main.java:948)