As per my understanding, use of Java reflection API slows down code execution by orders. But then I see it being used in so many places in Java universe. To name a few :
Which implies that there's some fact about java reflection (aka optimization technique) that I have missed out on. Any pointers ?
Main point: because they have no other choice.
Java is not a dynamic language, so the only way these frameworks can provide their services is by reflection.
Second, notice that most of the reflection work these framework do happens only once, during initialization, so the runtime performance is not affected.
There is one distinction that I notice being mixed up all the time:
Number 1 is slow (this is the "orders" you mention); number 2 is the one that has received significant speed improvements and is now only a couple of times slower than native access.