Question

I have just learned how to use exceptions, and I have a bit of confusion with RuntimeExceptions since these specifically are unchecked. So I have this code:

    String path = "foo/bar/local/stuff.txt";
    File file = new File(path);

Isn’t this not a FileNotFoundException if that path isn’t found? How do I specify that in my method? Also after this step I do:

    File[] listFiles = file.listFiles();

Doesn’t that also throw an exception if:
1. It’s not a directory, it’s a file.
2. It doesn’t exist.

Sorry if this seems like newbie questions, I still don’t really know how to use exceptions. Can someone please clarify?

Answer 1

Alright, I’m adding code, so I’m just gonna add a new answer. The listFiles method will return null if the file is not a directory. To throw your own exception, do this:

public void exampleMethod() throws Exception {
    File[] files = someFile.listFiles();
    if(files == null) {
        throw new Exception("File is not a directory, and as such cannot list files");
        //You can also create your own exception class (extends Exception), and explicitly throw that, rather than just a general Exception
        return;
    }

}

If you just want it to print the stuff, and not throw an exception, just do

new Exception("blah").printStackTrace();