How to change from -source 1.6 to -source 7 in IntelliJ IDEA

intellij-idea, java

Solution

Ctrl+Alt+Shift+S (Project Structure icon)

Then change Project language level

Problem

I' trying to build a in IntelliJ IDEA project that is not mine and I got the following error: java: diamond operator is not supported in -source 1.6 (use -source 7 or higher to enable diamond operator) How do I change this setting in IntelliJ IDEA?

Original source