Hands-On Microservices with Spring Boot and Spring Cloud

Dealing with blocking code

In the case of the review service, which uses JPA to access its data in a relational database, we don't have support for a non-blocking programming model. Instead, we can run the blocking code using Scheduler, which is capable of running the blocking code on a thread from a dedicated thread pool with a limited number of threads. Using a thread pool for the blocking code avoids draining the available threads in the microservice (avoids affecting the non-blocking processing in the microservice).

Let's see how this process works, as laid out in the following steps:

1. Firstly, we configure the thread pool in the main ReviewServiceApplication class, as follows:

@Autowiredpublic ReviewServiceApplication ( @Value("${spring.datasource.maximum-pool-size:10}") ...