Does spring @Scheduled annotated methods runs on different threads?

The documentation about scheduling says:

If you do not provide a pool-size attribute, the default thread pool will only have a single thread.

So if you have many scheduled tasks, you should configure the scheduler, as explained in the documentation, to have a pool with more threads, to make sure one long task doesn't delay all the other ones.

If you're using Spring Boot:

There is also a property you can set in your application properties file that increases the pool size:

spring.task.scheduling.pool.size=10

Seems to be there since Spring Boot 2.1.0.

For completeness, code below shows the simplest possible way to configure scheduler with java config:

@Configuration
@EnableScheduling
public class SpringConfiguration {

    @Bean(destroyMethod = "shutdown")
    public Executor taskScheduler() {
        return Executors.newScheduledThreadPool(5);
    }
    ...

When more control is desired, a @Configuration class may implement SchedulingConfigurer.