- Java 6 is not implemented on Leopard
- mobile phone specs on the vendors web sites don't list Java as a feature, something like Java ready sticker
- lack of tools
- diversity of frameworks and their life-span uncertainty
- growing complexity of the language itself
- dynamic languages that from their perspective are taking over Java current and future believers
I might be wrong because I don't follow the Java world on daily basis but my overall impression was that both audience and guests were not really happy what they came up with. But there is a good chance that they weren't actually upset but simply tired :) because of the fact that the discussion finished around 10 pm. I hope that a few pints after the launch let them recharge the batteries because the conference itself looks interesting.