Oh god, there were so many boneheaded 90s predictions about computers. 1) We just expected single core performance to double forever every 2 years or so. Many of us were ignorant of single-core performance scaling and the memory wall issues. I want to be clear: Computer Architects were warning people about this in the early 90s but many ignored their inconvenient truth. 2) 2D GUIs would evolve into 3D GUIs - maybe VR…
By the late 90s it was fully expected that Java would take over everything. And it did kinda for a while.
However that was more of an afterthought- I remember that when it came out I initially bought into the write-once-run-anywhere hype and the idea that Java was for writing applets.
The UIs were too clunky (AWT) or foreign (Swing, the second attempt) and the Java SDKs buggy so in the end HTML just improved faster and took over the presentation layer together with Futuresplash (later renamed to Flash).