The name Sun Microsystems is one that I, and most people, associated with microsystems - with workstations (and servers). Sun was founded in 1982 with Bill Joy as a founder, who was already a renowned programmer from CSRG. Andy Bechtolsheim had an exciting hardware design. Vinod Khosla and Scott McNealy risked starting a new company, and had enough chops to manage it into a success. Sun IPOd in 1986. Sun almost bought Apple right before Java was released.
Java was released in 1995. Sun Microsystems already had over a billion and a half dollars in revenue a quarter, which was pretty good at the time.
One reason for Java was protective - Sun wanted a language people could run on workstations and servers that it had some say over. A free, open source language was part of that, it helped in its adoption. Java was more of a defensive move, that Sun wouldn't be locked out of some kind of language ecosystem controlled by Microsoft or Netscape or other companies.
Sun wasn't a software company, they were a hardware company that released a product to defend their hardware from being locked out of competitor's ecosystems. They also weren't in a position to put out a computer language and force programmers onto it, being free and open source, and the ability to run on multiple platforms helped in its acceptance. Being able to run on multiple platforms was the whole point, they didn't want people to get locked into the Microsoft ecosystem with the release of NT 3.51 etc.