'Java -> operator

I know that -> is used for lambda expressions with the syntax ()->{}.

But I saw this code: file -> file.isFile() - with no () and {}. What does it do?

javaoperators


Solution 1:[1]

() is not required when you have a single argument and {} is not required when your lambda body is a single expression.

See the Java tutorial for further information and the Java Specification for a more formal description of the syntax.

Solution 2:[2]

As Federico answered, for the single arguments you do not need () and for the statements only return a value and do not do anything else, you do not need {}.

The addition I want to make to his contribution:

The code you put means, there is a function, that takes file as a parameter. Then, returns its .isFile().

In other words, you can also reach the same aim by defining a method:

<private/protected/public> boolean myLovelyMethod(File file){
    return file.isFile();
}

Lambda function just makes it a little bit shorter. If you are not going to re-use the method, may be better to use lambda.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Federico klez Culloca
Solution 2 Mark Rotteveel

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