Dear Sir,

I have compiled CreateKeyStores, HTTPSClientExample and HTTPSServerExample classes. However, when I try to run HTTPSClientExample (after HTTPSServerExample is run), I get the following error:

Exception in thread "main" javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderE xception: unable to find valid certification path to requested target
at com.sun.net.ssl.internal.ssl.Alerts.getSSLExceptio n(Alerts.java:174)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(S SLSocketImpl.java:1611)
at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Ha ndshaker.java:187)
at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Ha ndshaker.java:181)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.serv erCertificate(ClientHandshaker.java:1035)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.proc essMessage(ClientHandshaker.java:124)
at com.sun.net.ssl.internal.ssl.Handshaker.processLoo p(Handshaker.java:516)
at com.sun.net.ssl.internal.ssl.Handshaker.process_re cord(Handshaker.java:454)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRec ord(SSLSocketImpl.java:884)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.perform InitialHandshake(SSLSocketImpl.java:1112)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHa ndshake(SSLSocketImpl.java:1139)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHa ndshake(SSLSocketImpl.java:1123)
at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsC lient.java:418)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnect ion.connect(AbstractDelegateHttpsURLConnection.jav a:166)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect( HttpsURLConnectionImpl.java:133)
at HTTPS.HTTPSClientExample.main(HTTPSClientExample.j ava:72)
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderE xception: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXV alidator.java:285)
at sun.security.validator.PKIXValidator.engineValidat e(PKIXValidator.java:191)
at sun.security.validator.Validator.validate(Validato r.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.serv erCertificate(ClientHandshaker.java:1014)
... 11 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderE xception: 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(CertPathB uilder.java:238)
at sun.security.validator.PKIXValidator.doBuild(PKIXV alidator.java:280)
... 17 more

I am using the certificates generated by CreateKeyStores class, however, it seems like the error generated is related to the invalid certificate used by the client to connect to the server?

Could you please advise me on how I could possibly going about overcoming this error?

Many thanks in advance!