How many threads should I use in my Java program?

Question

I recently inherited a small Java program that takes information from a large database, does some processing and produces a detailed image regarding the information. The ori

Answer 1

The number that your application needs; no more, and no less.

Obviously, if you're writing an application which contains some parallelisable algorithm, then you can probably start benchmarking to find a good balance in the number of threads, but bear in mind that hundreds of threads won't speed up any operation.

If your algorithm can't be parallelised, then no number of additional threads is going to help.