public static boolean visitSdkRoots(@NotNull Sdk sdk, @NotNull RootVisitor visitor) {
    final VirtualFile[] roots = sdk.getRootProvider().getFiles(OrderRootType.CLASSES);
    for (VirtualFile root : roots) {
      if (!visitor.visitRoot(root, null, sdk, false)) {
        return true;
      }
    }
    return false;
  }
public static boolean visitSdkRoots(@NotNull Sdk sdk, @NotNull RootVisitor visitor)