Sun recently announced the release of a new technology (although it's not actually that new) called JavaFX. JavaFX is being touted as a Flash killer although personally I don't believe that it will be able to fully displace Flash any time soon. In theory at least JavaFX looks like a great idea. User interfaces in flash are fairly tricky to get right but applets are far to heavy weight for most situations. Something like JavaFX which sits in between may just have a space in the market. A lot is being made of the fact that JavaFX won't have the same video play back capabilities as flash but Flash is already handling that well and displacing that will be difficult and perhaps pointless. Start up time is, of course, very important. Sun are claiming that they can cut the JVM down to between 2 and 4 MB and are discussing a release of this slim VM with Java 6.0 Update 2. This should make loading much faster and of course make the download smaller and therefore more appealing.
Whether anything will come of JavaFX remains to be seen but I'm pretty interested in this and will explore it in more detail and list the results here. If JavaFX is to succeed Sun need to move fast to get it in the browser (currently it only works through Web Start) and follow through by promoting it and developing better development tools. Whether Sun will push JavaFX is the big question. They have come up with a lot of good ideas in the past but then failed to really do anything with them. Java is the prime example of this where they came up with a good idea and did nothing with it until Microsoft came knocking at the door. Only time will tell.