org.testng.TestNGException: while trying to execute the tests

Question

I have been working on a project using Android Studio since long. Today refactored some code and it started to break,so reverted the changes. Even after reverting the changes whenever I try to debug the code, I am ending up with following an exception :

org.testng.TestNGException: org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 44; Attribute "parallel" with value "none" must have a value from the list "false methods tests classes instances ".
    at org.testng.TestNG.initializeSuitesAndJarFile(TestNG.java:325)
    at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:90)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:206)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:177)
    at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:125)
Caused by: org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 44; Attribute "parallel" with value "none" must have a value from the list "false methods tests classes instances ".
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:396)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:284)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.validateDTDattribute(XMLDTDValidator.java:1392)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.addDTDDefaultAttrsAndValidate(XMLDTDValidator.java:1311)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleStartElement(XMLDTDValidator.java:1917)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:742)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:380)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:614)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3135)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:880)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:118)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:327)
    at javax.xml.parsers.SAXParser.parse(SAXParser.java:195)
    at org.testng.xml.XMLParser.parse(XMLParser.java:39)
    at org.testng.xml.SuiteXmlParser.parse(SuiteXmlParser.java:16)
    at org.testng.xml.SuiteXmlParser.parse(SuiteXmlParser.java:9)
    at org.testng.xml.Parser.parse(Parser.java:172)
    at org.testng.TestNG.initializeSuitesAndJarFile(TestNG.java:305)
    ... 4 more

trying to open the project using intelliJ I can get this gone. Any clues on this??

Answer 1

Discussion and help from @juherr suggests that solution to this is :

Attribute "parallel" with value "none" must have a value from the list "false methods tests classes instances ".

TestNG 6.9.10 is now validating the xml file against the DTD The problem is that the default testng.xml template from IntelliJ is setting "parallel" on suite to "none". Here is the link to the bug for the same.