What are the differences in multithreading implementations in Java and Kotlin applications?

In Java, multithreading is implemented through the Thread class and the Runnable interface, as well as using higher-level APIs from the java.util.concurrent package. Threads are created and managed manually, which requires careful control of synchronization and state.

In Kotlin, besides the standard Java mechanisms, coroutines are actively used — lightweight threads that allow writing asynchronous code in a simpler and more understandable way. Coroutines are managed by a scheduler and do not require creating system threads for each task, which improves performance and simplifies handling asynchronous operations.

Example of creating a coroutine in Kotlin:

import kotlinx.coroutines.*

fun main() = runBlocking {
    launch {
        delay(1000L)
        println("Hello from coroutine!")
    }
    println("Hello from main")
}

Thus, Kotlin offers a more modern and convenient way to work with parallelism compared to traditional Java.