Spring batch corePoolSize VS throttle-limit

The core pool size says a thread pool executor will start with N number of threads. A throttle-limit T says that, regardless of the number of threads available in the thread pool, only use T of those threads for a tasklet.

So you can have a thread pool with a core pool size of 8 and two tasklets with throttle limit of 4 in that case you will be utilizing your thread pool. But if you only have one tasklet with a throttle limit of 4 you will be utilizing one half of the thread pool.