I downloaded nutch-1.3.src and tried to build it with NetBeans IDE 7.0.1.

I searched online and found an article saying that I need to create a new “Java Project with Existing Sources”.

But when I tried to create that new project, on the second step: Add Source Package Folder, I met this problem:

The following folders that you selected are already used in this or another project. A package folder can only be used in one project in one package folder list (source packages or test packages)

I was confused quite a while. At last, I built a new folder and copied the folder “src” of nutch-1.3-src to the new folder and than chose that folder “” at the “add folder” step. It works just fine.