What is the return type of a lambda expression in Java?

The return type of a lambda expression in Java is inferred from the context in which it is used. This is determined by the functional interface to which the lambda expression is assigned. For example:

Function<Integer, Integer> doubleValue = (Integer x) -> x * 2;

In this case, the return type is inferred as Integer because the Function interface specifies an Integer as both the input and return type. This type inference feature of lambda expressions simplifies the syntax and makes the code more readable, as the return type does not need to be explicitly declared.

Type inference in lambda expressions is one of the key features that contribute to the concise and expressive nature of modern Java code. By reducing the need for explicit type declarations, lambda expressions allow developers to focus more on the logic they are implementing, making the code cleaner and easier to maintain.