Dafydd Walters has released JBarcodeBean 1.0.2, an open source JavaBeans component that can display bar codes on the client side or convert them to GIFs for serving to clients from the server side. JBarcodeBean is published under the LGPL.
Dieter Wimberger has written an open source telnet daemon in Java. It is designed to be "easily embeddable into other applications." This is published under a BSD license.