What is the meaning of “new {}” in Scala?

问题

I am studying about .sbt extension file reference docs. What codes I am confused is:

lazy val version = new {
    val finatra = "2.1.2"
}

I know val finatra can be accessed by version.finatra, but it seems like "object singleton." Such like this:

object version {
    val finatra = "2.1.2"
}

In this case, I can also access val finatra by version.finatra.
I know the later one is the way to create "object singleton". How about the former one? Thanks

回答1:

In short, it is creating new instance of Anonymous Type

According to the Scala Language Spec:

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Consider the following structural instance creation expression:

new { def getName() = "aaron" }

This is a shorthand for the general instance creation expression

new AnyRef{ def getName() = "aaron" }

The latter is in turn a shorthand for the block

{ class anon$X extends AnyRef{ def getName() = "aaron" }; new anon$X }

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来源：https://stackoverflow.com/questions/46825794/what-is-the-meaning-of-new-in-scala