including a new package in java

Firstly you don not include the package, but classes from a package. You can use the wildcard, so for example something like this will work:

import com.plumtree.openfoundation.security.IXPCrypto; // import the single class
import com.plumtree.openfoundation.security.*; // import the entire package

You also need to have the jar file in your library path.

Richard is clever, it's import not include; a sad case of Monday Morning Madness.