And if it's not run in a tight loop, the JIT can often still detect it. I don't know why you believe such things are trivial. On one occasion I altered some co

And if it's not run in a tight loop, the JIT can often still detect it. I don't know why you believe such things are trivial. On one occasion I altered some code which broke this, and it added about 10-20 seconds to a 15 minute HFT simulation. If that code made it to prod, those 10-20 seconds would be distributed around the hot parts of an HFT system. That's not remotely trivial, at least for performance critical applications (HFT, RTB, etc). In the second example, basically what happens (if you get lucky - I haven't found the JVM JIT to be super consistent) is that computation of cond and f(x) will be put into the pipeline together, and only the assignment to myVar will be conditional. This is strictly NOT something the CPU can do by itself, since there are side effects at the machine level (allocating objects, and then GCing them).