Java – IntelliJ switch statement uses string error: use – source 7

I tried to use IntelliJ (on Mac OS X) to compile some code I wrote using eclipse I tried to run the following code:

switch (category) {
    case "below 20":
        below20++;
        break;
    case "20 to 29":
        to30++;
        break;
    case "30 to 39":
        to40++;
        break;
    case "40 to 49":
        to50++;
        break;
    case "50 to 59":
        to60++;
        break;
    case "60 to 69":
        to70++;
        break;
    case "70 t0 79":
        to80++;
        break;
    case "80 to 89":
        to90++;
        break;
    case "90 to 99":
        above90++;
        break;
    default:
        break;
}

However, I received an error:

java: strings in switch are not supported in -source 1.6
  (use -source 7 or higher to enable strings in switch)

I know some answers will be: rtfe (i.e. replace manual and error) But I didn't I've tried the following:

>Preferences > compiler > java compiler and add - source 7 and / or - target to additional command line parameters > edit configuration: check to use alternative JDK and write to the directory / library / Java / javavirtualmachines / jdk1 7.0_ 51.jdk/Contents/Home

It hasn't been repaired yet What on earth did I do wrong?

Note: I know this is obvious because the directory is above, but I do have Java 7.0 installed

Thank you in advance!

Solution

In IntelliJ idea, you should also go to project settings – > project and set the appropriate project language level