Cannot run Doclet class given by Oracle

I want to experiment with Doclets (JDK 9), so I tried everything step by step given in this link. I have not add anything custom in Example class. It is exactly as Oracle gives it (I just declared the imports).

Oracle gives the command:

javadoc -doclet Example \
       -overviewfile overview.html \
       -sourcepath source-location \
       source-location/Example.java

Now when I run the given javadoc command, i get the following error:

javadoc: error - Cannot find doclet class Example

I tried some variations of the command since it seems to be a problem with directors but all of my tries have failed.

I place Example.java in my Desktop folder: C:\Users\George\Desktop\

So, in my command line I cd C:\Users\George\Desktop\. Then javac Example.java (in case it wants it compiled).

And then, i try all the following commands, getting the same error.

javadoc -doclet Example -overviewfile overview.html -sourcepath ./ ./Example.java

.

javadoc -doclet Example -overviewfile overview.html -sourcepath "C:\Users\George\Desktop\" "C:\Users\George\Desktop\Example.java"

(+without quotes)

javadoc -doclet Example -overviewfile overview.html"C:\Users\George\Desktop\Example.java"

I tried few other things found in SO, but again, nothing works. What am i missing? Should not the given example work?

Example class (in case you see something i do not):

public class Example implements Doclet {
    Reporter reporter;
    String overviewFile;

    public static void main(String[] args) {
    }

    public Example() {
        // TODO Auto-generated constructor stub
    }

    @Override
    public void init(Locale locale, Reporter reporter) {
        reporter.print(Kind.NOTE, "Doclet using locale: " + locale);
        this.reporter = reporter;
    }

    public void printElement(DocTrees trees, Element e) {
        DocCommentTree docCommentTree = trees.getDocCommentTree(e);
        if (docCommentTree != null) {
            System.out.println("Element (" + e.getKind() + ": " + e + ") has the following comments:");
            System.out.println("Entire body: " + docCommentTree.getFullBody());
            System.out.println("Block tags: " + docCommentTree.getBlockTags());
        }
    }

    @Override
    public String getName() {
        return "Example";
    }

    @Override
    public Set<? extends Option> getSupportedOptions() {
        Option[] options = { new Option() {
            private final List<String> someOption = Arrays.asList("-overviewfile", "--overview-file", "-o");

            @Override
            public int getArgumentCount() {
                return 1;
            }

            @Override
            public String getDescription() {
                return "an option with aliases";
            }

            @Override
            public Option.Kind getKind() {
                return Option.Kind.STANDARD;
            }

            @Override
            public List<String> getNames() {
                return someOption;
            }

            @Override
            public String getParameters() {
                return "file";
            }

            @Override
            public boolean process(String opt, List<String> arguments) {
                overviewFile = arguments.get(0);
                return true;
            }
        } };
        return new HashSet<>(Arrays.asList(options));
    }

    @Override
    public SourceVersion getSupportedSourceVersion() {
        return SourceVersion.latest();
    }

    @Override
    public boolean run(DocletEnvironment docEnv) {
        reporter.print(Kind.NOTE, "overviewfile: " + overviewFile);
        // get the DocTrees utility class to access document comments
        DocTrees docTrees = docEnv.getDocTrees();

        // location of an element in the same directory as overview.html
        try {
            Element e = ElementFilter.typesIn(docEnv.getSpecifiedElements()).iterator().next();
            DocCommentTree docCommentTree = docTrees.getDocCommentTree(e, overviewFile);
            if (docCommentTree != null) {
                System.out.println("Overview html: " + docCommentTree.getFullBody());
            }
        } catch (IOException missing) {
            reporter.print(Kind.ERROR, "No overview.html found.");
        }

        for (TypeElement t : ElementFilter.typesIn(docEnv.getIncludedElements())) {
            System.out.println(t.getKind() + ":" + t);
            for (javax.lang.model.element.Element e : t.getEnclosedElements()) {
                printElement(docTrees, e);
            }
        }
        return true;
    }
}

Running javadoc --help reveals the following option:

-docletpath <path>
              Specify where to find doclet class files

Use that option, and it should work fine (provided you compiled the Example class and it is indeed located in the directory passed as argument to this option).