Is Lambada (the Haskell-JNI bridge) gone? The web-page has disappeared. Using Java seems by far the most obvious way of getting all that GUI/network/SQL/whatever functionality, especially as the Java platform is almost ubiquitous (unlike .NET, Tk, X, GTK+, Win32 GDI, etc.).
I don't think it's in active development anymore, I think Erik Meijer has moved on to bigger and better things. I'm sure someone will correct me if I'm wrong... Erik mailed me a copy of Lambada last summer, but I found it rather limited for what I wanted it for (talking to an LDAP directory). I tried writing my own Lambada replacement using JNI/C/HDirect. This proved to be a nightmare - different bugs on different platforms, etc. I got it working for what I wanted on Linux, but it seg faulted on Sparc Solaris. I also had to add different hacks in for different platforms because of bugs in classpath handling. I eventually resorted to using just C and forgetting Java.
In this apparent absence I'm writing my own Haskell-JNI bridge.
Good Luck ! Chris.