Wotonomy is a pure java user interface framework for building both web and gui applications. It is heavily inspired by the NeXT and OpenStep APIs and it includes clean-room implementations of portions of the WebObjects and JavaClient frameworks.
Java developers will find the design patterns in wotonomy useful for reducing the complexities of data-driven application development. Swing developers will additionally find a number of useful Swing components and utilities.
OpenStep developers will find that they can use familiar APIs while still writing pure java applications. Wotonomy provides clean-room and API-compatible implementations of the EOInterface/EOControl, WebObjects, and Foundation frameworks that interoperate with and extend the Java Swing, Servlet, and Collections packages respectively. Wotonomy tries to be as API-compatible as possible while still tightly integrating with Java.
The current status of the framework is alpha. The user interface package is suitable for simple to moderate application development and has working associations for all Swing components and a display group that supports data sources, sorting, and delegates. Editing contexts are in development. The web package is a proof-of-concept implementation that currently only supports WOString. The foundation package has pure java ports of all classes needed by the ui and web packages, including NSArray and NSDictionary classes that implement the List and Map interfaces respectively.
GNUStep is awesome, but it's an Objective-C framework. The new Java bridge is great, but even Apple is backpedaling on that approach with their pure-Java version of WebObjects, due to performance problems and conceptual difficulties in development.
Wotonomy has the same license (GNU Lesser Public License), and is written completely in Java.
Yes, you should if at all possible. Then you'll get tools like InterfaceBuilder and EOModeler and ProjectBuilder and you'll be even more productive. But some of us have to deploy applications on Windows or Linux or MacOS9.
It's not an issue of free beer: WebObjects is worth at least ten times the price (which is currently way cheap at ~$500). It's the restrictions on deployment that create the problem.
The other problem is political. Perhaps if enough people adopt wotonomy for their Java projects, they'll see the advantage of investing in Apple technology. Additionally, applications using wotonomy will be extremely portable to Apple platforms.
Yes, it should be possible to get wotonomy running on JDK1.1, although it doesn't work right now. The collections packages would have to be renamed and the weak references would have to be looked at, but it looks do-able.
If your application used only NSArrays and NSDictionaries and no java2 collections, you could just link your app against a version of the wotonomy library built for 1.1 and it will just work.