I have posted this idea elsewhere but I think it deserves its own heading so people can comment on it.
This is a feature only Sun can provide, for technical and legal reasons, and although Tiger is a very mature product, I believe there remains one giant hole we need to plug in Mustang: JVM installation.
I am a strong believer in Java Webstart. The problem, though, is that the majority of the world's users use dial-up connections to the internet and a 2MB download translates into around 10 mins for them. There is absolutely no way for me, as a businessman, to get my product out to customers if they have to download anything over 2MB. Period. There is nothing I can do to fix this problem, period. Only Sun can (and should) help.
Mustang should combine the power of Java Webstart and PACK200 to provide a new sort of JRE installer. Here is the user-experience I am asking for:
1) User doesn't have Java or Java Webstart installed on their machine. He goes to my website, clicks on a Java Webstart link.
2) "The application you have selected requires Java Webstart in order to run. May I install it?"
3) User selects "YES"
4) Browser downloads a <2MB package that runs automatically, installs the JVM and launches Java Webstart.
5) Java Webstart downloads my application and runs it.
The key here is providing end-users with a "download-on-the-fly JRE". That is, ship Java Webstart with the absolute minimum dependencies. If it must be a native installer, so be it. This new version of Java Webstart would be smart enough so that if my application tries using a JRE core class/package that has not been downloaded yet, it'll go to Sun's server and download it automatically. As time passes, the user will get more and more classes installed on their machine and more applications will run out-of-the-box without having to download any JRE classes.
To me, this feature is the difference between life and death of my product. I also believe it will influence the future of millions of Java developers and will allow Java to enter the desktop domain. What do you think?