In Java what pros/cons exist surrounding the choice to use a.getClass() or A.class? Either can be used wherever a Class<?> is expected, but I imagine that there would be performance or other subtle benefits to using both in different circumstances (just like there are with Class.forName() and ClassLoader.loadClass().
I wouldn't compare them in terms of pros/cons since they have different purposes and there's seldom a "choice" to make between the two.
a.getClass() returns the runtime type of a. I.e., if you have A a = new B(); then a.getClass() will return the B class.
A.class evaluates to the A class statically, and is used for other purposes often related to reflection.
In terms of performance, there may be a measurable difference, but I won't say anything about it because in the end it is JVM and/or compiler dependent.