I think Java's problems on the desktop started before Oracle. There were issues like the loooooonnnnnggg delay to get the "consumer JRE" out, a few too many high-profile security issues, lack of up-to-date support for various media formats (despite the existence of "JMF", Java struggled a bit in the media world back then. And probably still does). There were also shortcomings with regards to accessing peripherals as I recall, although my memory is admittedly a bit fuzzy on some of that now.

That said, Oracle's legal machinations certainly didn't help matters once they took over.