JProxy
Provides HTTP tunneling for EJB, RMI, JNDI, JMS, and CORBA APIs for communication between client and J2EE and CORBA services. [Commercial]

ProProxy
Generic TCP/IP proxy. Handles UDP as well as TCP. [Open Source, GPL]

Java SOCKS Proxy
Supports SOCKS4 and SOCKS5 protocols, and Identd authentication. [Open Source, GPL]

RabbIT
Speeds up surfing over slow links by removing unnecessary parts (like background images) while still showing the page mostly like it is. Removes advertisements, compresses text, and images. [Open Source, BSD-like]

ZeeProxy
A HTTP proxy that serves web sites stored inside archives, decompressing files on-the-fly, as needed.

TCPReflector
Acts as a proxy for port forwarding. Gets around applet limitations on machines it can connect to. [Freeware]

Java Proxy
Lets you access computers behind a firewall. Includes SOCKS and Web proxy as a user program interface. [Freeware]

Java Anonymous Proxy - JAP
Acts as a local proxy between the browser and the insecure Internet. All web pages requested by the browser go directly to JAP, and are multiply encrypted there. The encrypted messages travel through a chain of servers (named Mixes by the inventor of the theoretical background, David Chaum) to the final destination on the Internet. [Freeware]

Smart Cache
Proxying, filtering cache server. Speeds up surfing and can block ad banners. Also has privacy features such as selective cookie filtering, changing HTTP referrer and browser name. [Open Source, GPL]

A-Proxy
A proxy server which realized by pure java language. It was design for home or enterprise using. By BirdsSoft.

Softon Tracking Proxy
Enable to monitor in real-time the content of the communication going through it. It could also be customized to simulate slow or fast data traffics and could be set to listen simultaneously on several ports and to connect to several specified hosts.

Net anonymity service back-doored
SecurityFocus reports the Java Anonymous Proxy (JAP), used to anonymise access to the Internet, has been back-doored by court order.

MailBridge
A HTTP tunnel for POP and SMTP to allow access from behind a firewall and acts as a local POP and SMTP server. It uses SWT for the GUI. [Freeware]

AnomicHTTPProxy
Terminal-based caching HTTP proxy with search engine. [Open Source, GPL]

PServer
Java internet proxy server and surveillance monitor written in 100% pure JAVA language. Handles HTTP, HTTPS, SMTP/POP3, FTP, SOCKSv5, TELNET. Also can detected and filtered out annoying Javascript PopUp windows, advertisements and promotions.