As a convenience, notes.jar is bundled in the com.ibm.notes.java.api plug-in to allow easy access, security, dependency, and path management. Depending on this plugin relieves your plugin from the responsibility of finding the notes.jar files and ensuring that your environment (system PATH and CLASSPATH ) is set up. The com.ibm.workplace.noteswc and the com.ibm.notes.java.api plugins take care of that. You cannot use the com.ibm.notes.java.api without the com.ibm.workplace.noteswc pluginl. Once you do this, you can just use the classes and objects in notes.jar as described in the Domino Designer documentation.
Set the BSAFE_ALLOW_REPARENT variable in your NOTES.INI to "BSAFE_ALLOW_REPARENT=1" to enable seamless security around the use of this plug-in. With this setting, you will be able to access the backend classes without multiple password prompts.