So if you run a Java program, under the JRE-xx you will get the maximum possible portability. I was the Director of Systems at FreeGate (an internet Appliance company) and we decided to do our 'UI' in Java, in the browser. (feeling it would give us wide reach) but at that time in particular (1996 - 2000) there was a lot of churn in the browser market and point releases of the browser could change significant behaviors.
Today that is less of an issue as pretty much everyone has punted on supplying their own version of Java for the browser and instead relying on the Snoracle version. However the UI compatibility is tied up inside the support for CSS and/or HTMLx where x is 4, 4.1, or 5 even.
Mobile apps for say Android which use their toolkit, and written in Java of course, are reasonably compatible across Android devices. However challenges with Honeycomb seem to have highlighted what happens when you change around some base assumptions. Even the migration from Android 1.6 and 2.0 was fraught with issues around new capabilities (and diverse capabilities) between handsets.
Configuration Management is a Hard Problem (tm) on any system and people see the Windows eco-system or the MacOS eco-system and feel like they should be able to do that cross-platform. I agree that if that problem gets solved in a meaningful way it will forever change the way we interact with our machines, but I don't think browsers are the great hope for cross platform compatibility.
Today that is less of an issue as pretty much everyone has punted on supplying their own version of Java for the browser and instead relying on the Snoracle version. However the UI compatibility is tied up inside the support for CSS and/or HTMLx where x is 4, 4.1, or 5 even.
Mobile apps for say Android which use their toolkit, and written in Java of course, are reasonably compatible across Android devices. However challenges with Honeycomb seem to have highlighted what happens when you change around some base assumptions. Even the migration from Android 1.6 and 2.0 was fraught with issues around new capabilities (and diverse capabilities) between handsets.
Configuration Management is a Hard Problem (tm) on any system and people see the Windows eco-system or the MacOS eco-system and feel like they should be able to do that cross-platform. I agree that if that problem gets solved in a meaningful way it will forever change the way we interact with our machines, but I don't think browsers are the great hope for cross platform compatibility.