JACOB is a very thin wrapper around COM IDispatch calls, so if you want to know how to do any particular task in Outlook the starting point would be the official Outlook Object Model documentation
Your particular case, locating and deleting a contact, is performed through
namespace = outlookApplication.GetNamespace("MAPI")
contactsFolder = namespace.GetDefaultFolder(olFolderContacts)
contact = contactsFolder.items.find( "[Email1Address] = 'mail@server.com' )
if (contact != null)
{
contact.Delete
}
The second half of the work is translating these calls to JACOB-speak. Assuming you have located your contact item, the code would be something like
ActiveXComponent outlookApplication = new ActiveXComponent("Outlook.Application");
Dispatch namespace = outlookApplication.getProperty("Session").toDispatch();
Dispatch contactsFolder = Dispatch.call(namespace, "GetDefaultFolder", new Integer(10)).toDispatch();
Dispatch contactItems = Dispatch.get(contactsFolder, "items");
String filter = String.format("[Email1Address] = '%s'", cont.getPrimaryEmail());
Dispatch contact = Dispatch.call(contactItems, "find", filter);
if (contact != null)
{
Dispatch.call(contactItem, "Delete");
}