A peer-to-peer software daemon and API to develop, deploy, discover and use components or applications over http without regard to type of hardware, OS, or programming environment. [Open source]

Language- and platform-independent protocol for peer-to-peer networking, developed by Sun. Initial implementation in Java. [Open Source, BSD-like]

Offers components for frequently used Internet protocols: FTP, HTTP, MIME, NNTP, POP3, SMTP, and telnet. [Commercial]

an agent development platform/framework for developing distributed, mobile, and reactive information agents with heterogeneous communication capabilities, in Java and JPython. [Open source, LGPL]

A Java object (de)serialization and messaging library which uses a more compact format than XML-RPC.

A class libraries for Java enable you to write applications to access, manage, update, and search for information stored in directories accessible using LDAPv3. Contributed by Novell. [Open source]

Includes early draft of JXTA text written by Brendon Wilson.

A library/framework for quick creation of robust and multi-threaded, multi-client TCP server applications. [Open source, LGPL]

Implementation of Sun's ONC/RPC protocol, both for clients and servers, including jrpcgen tool. [Open Source, LGPL]

Java components for SSH and telnet protocols.