Javamail Could not convert socket to TLS GMail

Question

I am trying to send an email using JavaMail through gmails SMTP Server. however this code.

final String username = "[email protected]";     final String password = "mygmailpassword";      Properties props = new Properties();     props.put("mail.smtp.auth", true);     props.put("mail.smtp.starttls.enable", true);     props.put("mail.smtp.host", "smtp.gmail.com");     props.put("mail.smtp.port", "587");      Session session = Session.getInstance(props,             new javax.mail.Authenticator() {                 protected PasswordAuthentication getPasswordAuthentication() {                     return new PasswordAuthentication(username, password);                 }             });      try {          Message message = new MimeMessage(session);         message.setFrom(new InternetAddress("[email protected]"));         message.setRecipients(Message.RecipientType.TO,                 InternetAddress.parse("[email protected]"));         message.setSubject("Testing Subject");         message.setText("Dear Mail Crawler,"                 + "\n\n No spam to my email, please!");          Transport.send(message);          System.out.println("Done");      } catch (MessagingException e) {         throw new RuntimeException(e);     } 

Returns an this error

Could not convert socket to TLS; 

The Complete Stacktrace

Exception in thread "main" java.lang.RuntimeException: javax.mail.MessagingException: Could not convert socket to TLS;   nested exception is:     javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target     at Test.main(Test.java:43) Caused by: javax.mail.MessagingException: Could not convert socket to TLS;   nested exception is:     javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target     at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1907)     at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:666)     at javax.mail.Service.connect(Service.java:317)     at javax.mail.Service.connect(Service.java:176)     at javax.mail.Service.connect(Service.java:125)     at javax.mail.Transport.send0(Transport.java:194)     at javax.mail.Transport.send(Transport.java:124)     at Test.main(Test.java:38) Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target     at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:174)     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1649)     at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:241)     at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:235)     at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1206)     at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:136)     at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:593)     at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:529)     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:893)     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1138)     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1165)     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1149)     at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:549)     at com.sun.mail.util.SocketFetcher.startTLS(SocketFetcher.java:486)     at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1902)     ... 7 more Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target     at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:323)     at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:217)     at sun.security.validator.Validator.validate(Validator.java:218)     at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:126)     at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:209)     at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:249)     at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1185)     ... 17 more Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target     at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:174)     at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:238)     at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:318)     ... 23 more 

Answer 1

props.put("mail.smtp.ssl.trust", "smtp.gmail.com"); 

Answer 2

I disabled avast antivirus for 10 minutes and get it working.