Is it possible to create and run a million threads simultaneously within one system?

Creating and simultaneously launching a million threads in a single system is practically impossible and impractical. Threads are resource-intensive objects, and the operating system limits their number due to memory constraints and the scheduler.

Instead, to handle a large number of tasks, thread pools (ThreadPool) or asynchronous models are usually used, which allow efficient management of a smaller number of threads by distributing tasks among them.

If you need to work with a million parallel tasks, it is better to use lightweight alternatives to threads, such as coroutines (in Kotlin), green threads, or asynchronous programming (CompletableFuture, reactive streams).

Thus, a million threads is technically and practically unachievable and inefficient.