Java Security

I'm having problems verifying an SSL client using Tomcat v5.x. I create a key in a particular keystore, let's call it C:\tomcat. I start tomcat specifying this file as the keystore to use. I then connect to the server on port 8443 with Internet Explorer and save the certificate returned from the server in a file. I then import the certificate into a keystore, let's say C:\tomcat_client. In my SSL client code I am specifiying the keystore to use with a System.setProperty("javax.net.ssl.trustStore", "C://tomcat_client"); However when I try to retrieve an output stream from a HttpURLConnection I receive the above exception. Any ideas what is happening ?

Exception : java.io.IOException: HTTPS hostname wrong: should be <localhost>

I have tried a variety of other options including importing the certificate into jssecacerts in the lib/security directory of the jre I am using to execute the SSL client, using the same keystore file for tomcat and the SSL client, etc.