Error while fetching from Google Scholar

Help
1

Up until yesterday, I was able to search using Google Scholar. However, yesterday and today, after I click to search for an item, I get an alert box saying “Error while fetching from Google Scholar”.

I am using JabRef 3.6. I can use Google Scholar in my browser too. How can I fix this?

This is what I’m getting in the error console log:

09:56:35.565 [AWT-EventQueue-0] INFO net.sf.jabref.logic.importer.OpenDatabase - Opening: C:\xampp\htdocs\Project\Research\Bibliography.bib
09:56:48.079 [SwingWorker-pool-3-thread-1] WARN net.sf.jabref.gui.worker.VersionWorker - Could not connect to the updateserver.
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.ssl.Alerts.getSSLException(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.processLoop(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.process_record(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source) ~[?:1.8.0_102]
at net.sf.jabref.logic.util.Version.getLatestVersion(Version.java:58) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.worker.VersionWorker.doInBackground(VersionWorker.java:37) [JabRef-3.6.jar:?]
at net.sf.jabref.gui.worker.VersionWorker.doInBackground(VersionWorker.java:18) [JabRef-3.6.jar:?]
at javax.swing.SwingWorker$1.call(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_102]
at javax.swing.SwingWorker.run(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_102]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 22 more
Caused by: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 22 more
Caused by: java.security.SignatureException: Signature does not match.
at sun.security.x509.X509CertImpl.verify(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.verifySignature(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.check(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 22 more
09:57:31.696 [JabRef CachedThreadPool] WARN net.sf.jabref.logic.net.URLDownload - Could not copy input
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.ssl.Alerts.getSSLException(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.processLoop(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.process_record(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(Unknown Source) ~[?:1.8.0_102]
at net.sf.jabref.logic.net.URLDownload.openConnection(URLDownload.java:110) ~[JabRef-3.6.jar:?]
at net.sf.jabref.logic.net.URLDownload.downloadToString(URLDownload.java:123) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.runConfig(GoogleScholarFetcher.java:156) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.processQueryGetPreview(GoogleScholarFetcher.java:82) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GeneralFetcher.lambda$actionPerformed$4(GeneralFetcher.java:191) ~[JabRef-3.6.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_102]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.SignatureException: Signature does not match.
at sun.security.x509.X509CertImpl.verify(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.verifySignature(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.check(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
09:57:31.702 [JabRef CachedThreadPool] WARN net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher - Error fetching from Google Scholar
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.ssl.Alerts.getSSLException(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.processLoop(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.process_record(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(Unknown Source) ~[?:1.8.0_102]
at net.sf.jabref.logic.net.URLDownload.openConnection(URLDownload.java:110) ~[JabRef-3.6.jar:?]
at net.sf.jabref.logic.net.URLDownload.downloadToString(URLDownload.java:123) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.runConfig(GoogleScholarFetcher.java:156) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.processQueryGetPreview(GoogleScholarFetcher.java:82) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GeneralFetcher.lambda$actionPerformed$4(GeneralFetcher.java:191) ~[JabRef-3.6.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_102]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.SignatureException: Signature does not match.
at sun.security.x509.X509CertImpl.verify(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.verifySignature(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.check(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
10:11:03.769 [JabRef CachedThreadPool] WARN net.sf.jabref.logic.net.URLDownload - Could not copy input
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.ssl.Alerts.getSSLException(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.processLoop(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.process_record(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(Unknown Source) ~[?:1.8.0_102]
at net.sf.jabref.logic.net.URLDownload.openConnection(URLDownload.java:110) ~[JabRef-3.6.jar:?]
at net.sf.jabref.logic.net.URLDownload.downloadToString(URLDownload.java:123) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.runConfig(GoogleScholarFetcher.java:156) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.processQueryGetPreview(GoogleScholarFetcher.java:82) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GeneralFetcher.lambda$actionPerformed$4(GeneralFetcher.java:191) ~[JabRef-3.6.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_102]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.SignatureException: Signature does not match.
at sun.security.x509.X509CertImpl.verify(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.verifySignature(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.check(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
10:11:03.774 [JabRef CachedThreadPool] WARN net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher - Error fetching from Google Scholar
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.ssl.Alerts.getSSLException(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.fatalSE(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.processLoop(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.Handshaker.process_record(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source) ~[?:1.8.0_102]
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(Unknown Source) ~[?:1.8.0_102]
at net.sf.jabref.logic.net.URLDownload.openConnection(URLDownload.java:110) ~[JabRef-3.6.jar:?]
at net.sf.jabref.logic.net.URLDownload.downloadToString(URLDownload.java:123) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.runConfig(GoogleScholarFetcher.java:156) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GoogleScholarFetcher.processQueryGetPreview(GoogleScholarFetcher.java:82) ~[JabRef-3.6.jar:?]
at net.sf.jabref.gui.importer.fetcher.GeneralFetcher.lambda$actionPerformed$4(GeneralFetcher.java:191) ~[JabRef-3.6.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_102]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_102]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.cert.CertPathValidatorException: signature check failed
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more
Caused by: java.security.SignatureException: Signature does not match.
at sun.security.x509.X509CertImpl.verify(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.verifySignature(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.BasicChecker.check(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at java.security.cert.CertPathValidator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.doValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source) ~[?:1.8.0_102]
at sun.security.validator.Validator.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source) ~[?:1.8.0_102]
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source) ~[?:1.8.0_102]
… 19 more

2

It sounds like you have reach the traffic limitations…
See http://help.jabref.org/en/GoogleScholarHelp
and https://github.com/JabRef/jabref/issues/1886

3

Thanks for you answer. I read those links already, and tried to use Google Scholar in my browser, as suggested here:

“To unblock your IP, do a Google scholar search in your browser. You will be asked to show that you are not a robot (a CAPTCHA challenge).”

However, a CAPTCHA challenge did not appear for me. Is there any other way to unblock my IP if I have been blocked?

4

At the moment, I do not see any other solutions than 1) waiting for the ban to end or 2) using JabFox…

5

Hello,

your problem seems to be a bit different, the exceptions in your stack trace indicate that you seem to have some problems with SSL certificates…

6

The error message

suggest that you have indeed some problems with SSL certificates. Normally Java is configured to automatically trust Google (and JabRef) but for some reason this does not work for you.
Maybe it works if you follow the procedure outlined in the answers on stackoverflow for google.de and jabref.de. But to be honest, I think your problem lies a bit deeper (since not only google.de is not trused anymore but also jabref.de as you have also problems with the update check). Maybe some admin configuration or proxy thing.

7

The problem with Google Scholar (encountered in version 3.6) is fixed in the current development builds which are available at https://builds.jabref.org/master .
So, if you do not want to wait for the release of JabRef 3.7 (date unknown), you may use the development version (as a precaution, backup your database).

Note: only the first 10 hits are returned.

8

This problem should be solved in the version 3.7 we have just released.