@Kit Menke Could you please let me know if you were able to call knox webhdfs via JAVA. I am trying same but I get the following exception at Hdfs.ls( session ).dir( "/" ).now().getString() log4j:WARN No appenders could be found for logger (org.apache.http.client.protocol.RequestAddCookies). log4j:WARN Please initialize the log4j system properly. log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. Exception in thread "main" org.apache.knox.gateway.shell.HadoopException: 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 org.apache.knox.gateway.shell.AbstractRequest.now(AbstractRequest.java:85) at webhdfsclient.program.main(program.java:23) 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:1959) at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302) at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296) at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1514) at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216) at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1026) at sun.security.ssl.Handshaker.process_record(Handshaker.java:961) at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1072) at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397) at org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket(SSLConnectionSocketFactory.java:396) at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:355) at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:373) at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:381) at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:237) at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185) at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89) at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:111) at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185) at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:72) at org.apache.knox.gateway.shell.Hadoop.executeNow(Hadoop.java:256) at org.apache.knox.gateway.shell.AbstractRequest.execute(AbstractRequest.java:50) at org.apache.knox.gateway.shell.hdfs.Ls$Request.access$200(Ls.java:31) at org.apache.knox.gateway.shell.hdfs.Ls$Request$1.call(Ls.java:51) at org.apache.knox.gateway.shell.hdfs.Ls$Request$1.call(Ls.java:45) at org.apache.knox.gateway.shell.AbstractRequest.now(AbstractRequest.java:83) ... 1 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:397) at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302) at sun.security.validator.Validator.validate(Validator.java:260) at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324) at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229) at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124) at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1496) ... 25 more Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141) at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126) at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280) at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392) ... 31 more ... View more