org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'explicit-platform'. One of '{"http://www.netbeans.org/ns/j2se-project/3":web-service-clients, "http://www.netbeans.org/ns/j2se-project/3":source-roots}' is expected.
   at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:0)
   at org.apache.xerces.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:0)
   at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:0)
   at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:0)
   at org.apache.xerces.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:0)
   at org.apache.xerces.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:0)
   at org.apache.xerces.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:0)
   at org.apache.xerces.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:0)
   at org.apache.xerces.jaxp.validation.DOMValidatorHelper.beginNode(DOMValidatorHelper.java:0)
   at org.apache.xerces.jaxp.validation.DOMValidatorHelper.validate(DOMValidatorHelper.java:0)
   at org.apache.xerces.jaxp.validation.DOMValidatorHelper.validate(DOMValidatorHelper.java:0)
   at org.apache.xerces.jaxp.validation.ValidatorImpl.validate(ValidatorImpl.java:0)
   at javax.xml.validation.Validator.validate(Validator.java:127)
   at org.openide.xml.XMLUtil.validate(XMLUtil.java:513)
   at org.netbeans.modules.project.ant.ProjectXMLCatalogReader.validate(ProjectXMLCatalogReader.java:149)
Caused: java.io.IOException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'explicit-platform'. One of '{"http://www.netbeans.org/ns/j2se-project/3":web-service-clients, "http://www.netbeans.org/ns/j2se-project/3":source-roots}' is expected.
   at org.netbeans.spi.project.support.ant.AntProjectHelper.saveXml(AntProjectHelper.java:343)
   at org.netbeans.spi.project.support.ant.AntProjectHelper.save(AntProjectHelper.java:624)
   at org.netbeans.spi.project.support.ant.AntProjectHelper.access$100(AntProjectHelper.java:113)
   at org.netbeans.spi.project.support.ant.AntProjectHelper$1.save(AntProjectHelper.java:151)
   at org.netbeans.modules.project.ant.AntBasedProjectFactorySingleton.saveProject(AntBasedProjectFactorySingleton.java:426)
   at org.netbeans.api.project.ProjectManager$6.run(ProjectManager.java:671)
   at org.netbeans.api.project.ProjectManager$6.run(ProjectManager.java:662)
   at org.openide.util.Mutex.writeAccess(Mutex.java:438)
   at org.netbeans.api.project.ProjectManager.saveProject(ProjectManager.java:662)
   at org.netbeans.modules.projectimport.eclipse.j2se.J2SEProjectFactory.createProject(J2SEProjectFactory.java:148)
   at org.netbeans.modules.projectimport.eclipse.core.Importer.importProjectStage1(Importer.java:236)
   at org.netbeans.modules.projectimport.eclipse.core.Importer.access$600(Importer.java:72)
   at org.netbeans.modules.projectimport.eclipse.core.Importer$3.run(Importer.java:181)
   at org.netbeans.modules.projectimport.eclipse.core.Importer$3.run(Importer.java:178)
   at org.openide.util.Mutex.writeAccess(Mutex.java:399)
   at org.netbeans.modules.projectimport.eclipse.core.Importer.importProject(Importer.java:178)
   at org.netbeans.modules.projectimport.eclipse.core.Importer.access$200(Importer.java:72)
   at org.netbeans.modules.projectimport.eclipse.core.Importer$1.run(Importer.java:111)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1452)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2032)