How can my application or applet programmatically use HTTPS to talk to a servlet? Can I do it with just the Java 2 SDK?
In order to use secure sockets, you need an SSL implementation. this is not provided in the Java 2 SDK.
If you are running an applet, the major browsers provide support for HTTPS through the java.net.URL class - simply specify a protocol of "https" in your URL string and the details are handled for you.
Sun provides a reference implementation of JSSE, along with sample programs, which you can download from http://java.sun.com/products/jsse/. It comes in both a "domestic version" (US/Canada) and an "export version" (all other countries).