From ISNetworks. Can be use as application or applet. [Open source, GPL]

Provides VT320/ANSI emulation. It can be used to provide access to telnet services via a Java capable WWW browser. [Open Source, GPL/LGPL]

IBM 3270 and Tandem 6530 terminal emulators and APIs for the Java Platform. (Platypus Partners) [commercial]

Complete SSH-client with a vt100 terminal. [Open Source, GPL]

A Java implementation of telnet/SSH and ANSI/vt320 terminal emulation. [Open Source, GPL]