Normally editors just states that the file does not exist, but here we are comparing null with some current text...

java.lang.NullPointerException
at org.jboss.tools.common.model.ui.texteditors.XMLTextEditorComponent.isEqualText(XMLTextEditorComponent.java:223)
at org.jboss.tools.common.model.ui.texteditors.TextEditorSupport.update(TextEditorSupport.java:46)
at org.jboss.tools.common.model.ui.texteditors.TextEditorSupport.setObject(TextEditorSupport.java:33)
at org.jboss.tools.common.model.ui.texteditors.XMLTextEditorComponent.setObject(XMLTextEditorComponent.java:81)
at org.jboss.tools.common.editor.ObjectMultiPageEditor.initEditors(ObjectMultiPageEditor.java:457)
at org.jboss.tools.jst.web.ui.editors.WebCompoundEditor.doCreatePages(WebCompoundEditor.java:29)
at org.jboss.tools.common.editor.ObjectMultiPageEditor.createPages(ObjectMultiPageEditor.java:220)
at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:283)
at org.jboss.tools.common.model.ui.editor.EditorPartWrapper.createPartControl(EditorPartWrapper.java:102)
at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:661)
at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:426)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:592)
at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:299)