intellij idea - Java "lambda expressions not supported at this language level"

Question

I was testing out some new features of Java 8 and copied the example into my IDE (Eclipse originally, then IntelliJ) as shown here

Eclipse offered no support whatsoever for lambda expressions, and IntelliJ kept reporting an error

Lambda expressions not supported at this language level

I would like to know if this is a problem with my install, the code, or support.

Answer 1

In IntelliJ IDEA:

In File Menu → Project Structure → Project, change Project Language Level to 8.0 - Lambdas, type annotations etc.

For Android 3.0+ Go File → Project Structure → Module → app and In Properties Tab set Source Compatibility and Target Compatibility to 1.8 (Java 8)

Screenshot: