javax.mail.MessagingException: Could not convert socket to TLS

javax.mail.MessagingException: Could not convert socket to TLS:

You may get this error when you are trying to send an e-mail using gmail server in java.

Complete Error:

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 checkmail.main(checkmail.java:64)
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:367)
at javax.mail.Service.connect(Service.java:226)
at javax.mail.Service.connect(Service.java:175)
at javax.mail.Transport.send0(Transport.java:253)
at javax.mail.Transport.send(Transport.java:124)
at checkmail.main(checkmail.java:59)
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 sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1902)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:276)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:270)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1338)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:154)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:868)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:804)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1032)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1328)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1355)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1339)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:528)
at com.sun.mail.util.SocketFetcher.startTLS(SocketFetcher.java:465)
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:385)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:292)
at sun.security.validator.Validator.validate(Validator.java:260)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:326)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:231)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:126)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1320)
… 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:196)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:268)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:380)
… 23 more
Java Result: 1

SOLUTION:
Add this line to your properties ,

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

For Complete code for sending E-mail using gmail, Visit Here

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Sending Email Using Java

Sending Email Using Java

Here is the code to send email using Java. Here we are going to use gmail gateway to send emails.
Please follow these steps before you use this code:
1. Login your google account
2. In google search, search “Application-specific password”
3. Enter a label for your reference and select “generate password”
4. Copy that password and paste it in code at “//password here” line.

Tested in NetBeans 8.0

 

 

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