Besides the fact that James Gosling has been inescapably tagged as "The Inventor Of Java" (which is undoubtedly true - he was on the project from day one, designing the language, writing the first compiler), the original roots of Java actually go back to a guy named Patrick Naughton. Naughton, a young, talented software engineer, had been working at Sun Microsystem's "NeWS"-group from 1988 on. Gosling - the group's lead - became Naughton's mentor.
Still, in 1990 Patrick Naughton was about to leave Sun. His "X11/NeWS"-project was going nowhere. Steve Jobs' NeXTSTEP was the hot new thing at that time, and Jobs offered Naughton a job at NeXT.
When Naughton told Scott McNealy about his resignation at the "Dutch Goose" in Menlo Park (some Sun folks had met there for beers and burgers, after one of Sun's famous employee hockey games), McNealy tried to convince him to stay with Sun, at least postpone his departure. When he did not succeed in that, McNealy asked Naughton for a memo describing what he would to change at Sun.
Naughton suggested reducing project staffing by an order of magnitude, where the remaining small core of people could do more to effect change quickly than they would ever get with any compromise solutions. He wanted to do fewer things, but do those fewer things better.
Says Naughton: "I lined up a sequence of suppositions for why projects fail inside of Sun that made a firm argument for creating a group that had complete autonomy from mainline Sun. I suggested that we would need to be completely secret, a black project. We would move off campus to some non-descript locale nearby, like the NFS group had done in Menlo Park a few years earlier. We would have to have a tiny group of people, not larger than a round table at Little Garden, our favorite Schezchuan/Hunan Chinese place in Palo Alto. We would get to hand pick a few senior contributors from inside of Sun, then go outside for art and design help. We would be exempt from the Sun Product Strategy Committee guidelines about using SPARC, Solaris and OPEN LOOK. In fact, we would explicitly build for some other platform, not at all like a workstation."
McNealy accepted, and added a significant salary raise, so Naughton stayed. This was the dawn of project "Green" (later: "Oak"), which took some more interesting twists, which Naughton describes in detail in "The Long Strange Trip to Java". The rest is history.
Naughton bailed out in 1994 after some dispute with his vice president, just some months before Java was introduced to the public as how we know it today (in 1993, Sun had tried to sell "Oak" in the consumer electronic market as a system-platform for set-top boxes).
Less well known is what happened with Naughton afterwards. He became CTO at a company named Starwave, and later VP at Infoseek/Go Network/Disney. In 1997 Naughton wrote an autobiographic article for Forbes: "Mr. Famous Comes Home".
More information from Sun: "Java Technologies - The Early Days". Naughton appears on the team's group photo. This page also includes a screenshot of "Webrunner" (later: HotJava browser), which had been developed by - Patrick Naughton.