HotJava was pretty much proof that you could have Java well integrated into the browser. If you can do the browser entirely in Java and run applets smoothly, then there is no reason why a "better" browser runtime/implementation couldn't be even smoother.
The problem was that the browsers were busy loading up on every feature they could (including JavaScript) while also providing Java runtimes that would load after the fact (and the Java load times were often much better than the browser load times, but since the Java runtime load was deferred, it was a much more painful experience).
You could keep browsers lightweight by doing much of the stuff browsers were doing into Java, but the problem with that is that the browsers were in a race to differentiate from each other, and the whole point of Java was that the experience was uniform. So instead we got a rush of poorly considered browser capabilities that we were stuck with for an extremely long time.
I can't blame the browser makers... Sun never came up with a business proposition for them that encouraged focusing on a better Java experience.
The problem was that the browsers were busy loading up on every feature they could (including JavaScript) while also providing Java runtimes that would load after the fact (and the Java load times were often much better than the browser load times, but since the Java runtime load was deferred, it was a much more painful experience).
You could keep browsers lightweight by doing much of the stuff browsers were doing into Java, but the problem with that is that the browsers were in a race to differentiate from each other, and the whole point of Java was that the experience was uniform. So instead we got a rush of poorly considered browser capabilities that we were stuck with for an extremely long time.
I can't blame the browser makers... Sun never came up with a business proposition for them that encouraged focusing on a better Java experience.