Here’s a curious little story. Google apparently recruits some coders based on search queries. What happens is that visitor is presented with a coding challenge (which may involve Linux or Unix as well as Windows), apparently with java (maybe other OOL’s) and a deadline to solve it. The visitor could simply decline the invitation. Quora describes the process here.
Coding challenges might become more common in the future.
As early as 1999, the knowledge required for java certification was enormous, as shown by a Sybex book on certification prep, for a language first implemented by Sun in 1995. I took a one-week course in February 1999 while working for ReliaStar (in Minneapolis) but never quite crossed the threshold nof getting fluent with it. The transition for older mainframe programmers could be difficult.
Had I gotten into the mid-tier Data Access area in 1999 rather than staying on mainframe (for Y2K) my history might have been different. I can remember a conversation with my boss about this at a company team function on a river boat on Sept. 11, 2001, before we knew the complete ramifications of that day.