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 com.plumtree.openfoundation.security.*;
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.