in principal 1 sample delay.
output goes back through input, but must of course first being processed.
the processSample function (of the super Module, but then as an object.....) is called 48.000 times per second, the internal sample rate of VM.
of course it depends on how a module is designed (sometimes something can't be done without introducing delay, if there is more latency or delay, per module.
and java was always multi-threaded, so processSample, does not have to all the work of course.. but timing issues. of course it is the developer that makes everything steady, that all is in time, just in time....
in my experience it works, never encountered this problem, and if i encountered it, i used it...
but it can be a problem;
there is certainly one module that can 'fix' this, a delay module (delay for processing..). or a plugin via plugin host, for example, can add latency. so, for these kinds of problems are solutions, and thes solutions can also be used the other way around, modular!
(disclaimer: i am not a developer, i am starting to design, on paper a module, but will take a lot of time, because my main focus is making music... java isn't the problem...)