Simple tool to save certificate chain certificates as PEM files

It’s been increasingly frustrating to support our OnTime Group Calendar for Microsoft customers with on-prem Exchange as they usually use a self-signed certificate for TLS resulting in Java throwing a fit. Getting the certificate chain using a browser or OpenSSL is easy enough but for some customers that still prove too difficult. I couldn’t find a tool to automate the export so I wrote a small tool in Java. The tool simply takes the address of the site to contact and saves the certificate chain as individual PEM files ready for import into the Java keystore. Now there is no fingerprint check so use at your own risk. Using the tool is like so:

java Main http://www.ibm.com

The code is available on Github and doubles as an example of how to accept all certificates using a custom TrustManager and HostNameVerifier. I even threw in some Java 8 to make Rene happy 😦

YMMV…