Enthuware. Is this a valid lambda expression?

What will the following code print?

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W3 Schools wrote:Expressions are limited. They have to immediately return a value, and they cannot contain variables, assignments or statements such as if or for. In order to do more complex operations, a code block can be used with curly braces. If the lambda expression needs to return a value, then the code block should have a return statement.

The Java Language Specification, Java SE 22 Edition wrote:Any local variable, formal parameter, or exception parameter used but not declared in a lambda expression must either be final or effectively final (§4.12.4), as specified in §6.5.6.1.

Any local variable used but not declared in a lambda body must be definitely assigned (§16 (Definite Assignment)) before the lambda body, or a compile-time error occurs.

Stephan van Hulst wrote:You can also use assignments, as long as the assigned variable is a lambda parameter. It doesn't actually do anything useful, but it's possible.

Anil Philip wrote:I did not understand this bit. It definitely does something useful - increments each item in the list.

In my original question, I was asking; isn't this a statement that requires a semi-colon and braces?

Stephan van Hulst wrote:

Anil Philip wrote:I did not understand this bit. It definitely does something useful - increments each item in the list.

Then comment it out and see what your application prints.

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Stephan van Hulst wrote:The part about assignments and variables is just wrong.

Anil Philip wrote:surprised! But I understand now what you meant.

Mike Simmons wrote:

Anil Philip wrote:surprised! But I understand now what you meant.

Do you understand why it doesn't do anything?

Anil Philip wrote:Yes. It should have done a set () to change anything.

The behavior of this method is unspecified if the action performs side-effects that modify the underlying source of elements, unless an overriding class has specified a concurrent modification policy.