title: SQL Developer error
body: <p>I'm trying to use SQL developer, but it won't connect using the proxy I specify in the preferences. I guess it's because of some kind of certificate error? Not sure. I'm getting the error:</p>
  
  <p>No HTTP response received.</p>
  
  <p>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:1591)
      at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:187)
      at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:181)
      at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:975)
      at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:123)
      at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:516)
      at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:454)
      at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:884)
      at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1096)
      at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1123)
      at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1107)
      at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:405)
      at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:166)
      at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:133)
      at oracle.ide.webbrowser.HttpPing$PingRunnable.run(HttpPing.java:109)
      at oracle.ide.webbrowser.ProxyOptions.doTask(ProxyOptions.java:522)
      at oracle.ide.webbrowser.HttpPing.ping(HttpPing.java:74)
      at oracle.ide.webbrowser.ProxySettingsPanel$5.run(ProxySettingsPanel.java:766)
      at java.lang.Thread.run(Thread.java:619)
  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:285)
      at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:191)
      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:954)
      ... 15 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:280)
      ... 21 more</p>