Can you tell me about the key features of the type system in Kotlin?

Key features of the type system in Kotlin:

• Static typing: Types are checked at compile time, helping to avoid many errors.
• Null safety: Kotlin has a built-in system for working with nullable types, reducing the number of NullPointerException errors. For example, the type String? can contain null, while String cannot.
• Type inference: The Kotlin compiler can infer the types of variables and functions, simplifying the code.
• Upper and lower type bounds: Kotlin supports inheritance and interfaces, allowing the construction of type hierarchies.
• Coroutines and types: Types can be used in coroutines for asynchronous programming.

Example of null safety:

var a: String = "Hello"
var b: String? = null

println(a.length) // always safe
// println(b.length) // compile error
println(b?.length) // safe call, returns null if b == null

These features make Kotlin a convenient and safe language for development.