This is a well known pattern in services now too, lots of platforms are buying user market share by offering free/cheap service for college students and reaping the revenue when the students move on / generate invites.
I wouldn't call this bribes but you can make an argument that it's buying mindshare that you wouldn't get on your own merits.
Quite to the contrary. If anything, Java was helping sales of future Sun boxes, rather than the other way around. Sun worked hard to make sure Solaris ran Java efficiently and stably, so if you were a Java developer you might consider Sun boxen professionally.
Sun didn't need to bride our teachers, doing the same in C and C++ was such a pain with 1996 compilers and POSIX, that they didn't thought twice about changing into an interpreted language.