macOS Make a new Folder with Java

Hey

I wondered how you created a new folder or directory with java, when in xcode with the code

File f=new File("/test");
if(f.exists()==false){

f.mkdirs();​

}
it produces two cannot find symbol errors on the first line. Why is this? how do I create a directory with Java on Mac OS X?

Thanks

Matthew

Thanks, I knew it'd be something like that.