Since you don't really need the total number, and in fact want to perform an action after a certain number (in your case 5000), you can use java.nio.file.Files.newDirectoryStream. The benefit is that you can exit early instead having to go through the entire directory just to get a count.
public boolean isOverMax(){
Path dir = Paths.get("C:/foo/bar");
int i = 1;
try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
for (Path p : stream) {
//larger than max files, exit
if (++i > MAX_FILES) {
return true;
}
}
} catch (IOException ex) {
ex.printStackTrace();
}
return false;
}
The interface doc for DirectoryStream also has some good examples.