return a value from a thread c++ code example

Example 1: java function without return

//The Function type is declared as

interface Function<T,R> {
  R apply(T t);
}
//And the Consumer type is declared as

interface Consumer<T> {
   void accept(T t);
}
//Consumer is compatible with methods that receive
//a T and return nothing (void).

Example 2: return type in kotlin function

//Function having two Int parameters with Int return type
fun sum(a: Int, b: Int): Int {
    return a + b
}