Kotlin in Action, Second Edition

Kotlin coroutines provide lightweight, suspendable computations that allow asynchronous code to look sequential and avoid blocking threads. [1] [2]

Structured concurrency organizes coroutines into parent-child hierarchies, ensuring that parent coroutines wait for their children and manage their cancellation automatically. [1] [2]

Cold flows emit values only when collected by a subscriber, while hot flows broadcast values to multiple subscribers regardless of collection. [1] [2]

State flows are ideal for representing state with a single current value, while shared flows are better for broadcasting events to multiple subscribers. [1]

Kotlin provides a rich set of flow operators for transforming, buffering, filtering, and combining flows, enabling advanced stream processing. [1] [2]

Kotlin uses structured concurrency to propagate exceptions, supports supervisors to isolate failures, and provides operators for handling errors in flows. [1] [2]

Kotlin offers virtual time, specialized test dispatchers, and libraries like Turbine for fast and reliable testing of coroutines and flows. [1]

Kotlin’s support for lambdas with receivers and the invoke convention enables expressive, type-safe DSLs for tasks like HTML building and test frameworks. [1] [2]

Reified type parameters allow runtime type checks, while variance annotations provide flexibility and safety in generic API design. [1] [2]

Popular tools include Kotest and MockK for testing, kotlinx.benchmark for benchmarking, and Dokka for documentation generation. [1] [2]