What is the difference between threads and coroutines in Kotlin?

Threads and coroutines are both mechanisms for concurrent programming in Kotlin, but they operate at different levels of abstraction and have distinct characteristics.

• Threads: Threads are heavyweight units of execution managed by the operating system. Each thread has its own stack and consumes system resources, making thread creation and management relatively expensive. Threads provide true parallelism and can execute multiple tasks simultaneously on multicore CPUs.
• Coroutines: Coroutines, on the other hand, are lightweight units of execution managed by the Kotlin runtime. Coroutines are cooperative and share resources, allowing for more efficient concurrency and resource utilization compared to threads. Coroutines provide concurrency at the application level and enable asynchronous and non-blocking programming paradigms.

The key differences between threads and coroutines in Kotlin include:

• Concurrency model: Threads operate at the operating system level and provide true parallelism, while coroutines operate at the application level and provide cooperative multitasking.
• Resource consumption: Threads consume more system resources due to their heavyweight nature, while coroutines are lightweight and consume fewer resources, making them more efficient for concurrent programming.
• Concurrency control: Threads require explicit synchronization mechanisms like locks and semaphores to coordinate access to shared resources, while coroutines use constructs like suspend and resume to manage concurrency and synchronization.
• Error handling: Threads have implicit error propagation and exception handling mechanisms, while coroutines provide more structured error handling using try-catch blocks and coroutine cancellation mechanisms.

Understanding the differences between threads and coroutines is essential for choosing the appropriate concurrency model based on the requirements and constraints of the application.