I know of three PhD's in comp sci that went straight into Goldman Sachs (and one hedge fund) where they immediately started earning far more than those of us that left Uni with our Bachelors.
They work in high frequency trading mainly using Java.
They work in high frequency trading mainly using Java.
I supported a derivatives trading system written in java that was canned due to performance issues, and where I am now we had java FIX protocol gateways that we've replaced with C++ components, again for performance reasons.
I'm not saying java has performance problems in general, I do understand that for many applications it's a good and performant option, but when you're dealing with sub-millisecond response times it has issues. If anyone is using Java for applications like this, I'd love to know how they get round these issues.
* look at memory mapped data in java (basically using sun.misc.Unsafe lets you deal with things like malloc and free)
* look at increasing use of primitives and collections that utilize primitives appropriately
* properly profile / size your eden space
yada yada ... i think a lot of HN people have generally just wrote off java as not as fast as C, not as productive as python/ruby, and not as exciting as lisp, haskell, FOTM. Java's a fine tool like anything else...just need to use it appropriately.
AFAIK, mark-and-sweep GC was removed from the JVM years ago (except on Android, where Dalvik used it until 2.something). I can't help with the rest of your post though.
But here I am.
Most PhD people I've met (selection bias) don't do work that's too closely related to their degree (just like I don't, Enterprise Java dev != comp sci). They do all make a lot of money though.
I'm just showing you how it's possible to do a PhD then get a good paying job at the end. This removed the worry of missing out on 5 years of salary.
Why do people want degree graduates? Because it shows they can finish things, because it shows they are smart? because it shows they have drive? Many reason are given for hiring grads.
Somebody with a PhD in comp sci would have pretty much proven they are good with very difficult problems and have the drive to see things through to completion.
What qualities do you think it takes to finish a PhD? Some employers seek out those qualities and a PhD is a good indication that you have those qualities.