loading Java Class into Oracle Database through TOAD

While the referenced question is similar it speaks to putting the source code into the database not the class, also I would like to use the TOAD utilities to accomplish this.

So as proof of concept I have been attempting to load a java class into an Oracle 12c Database and access it via an Oracle function.

I opened Eclipse and created new project Hello with class Hello:

public class Hello {

  public static String world()
    {

      return "Hello world";

    }

}

I compiled it and now on my client I have

C:\Users\me\workspaces\Hello\bin\Hello.class

I opened up TOAD for an oracle 12c database, then I went to utilities / Java Manager and loaded my class:

TOAD says it successfully loaded. However, I'm not sure if it did.

Next, I went into the TOAD editor and created a function:

CREATE OR REPLACE function "DIR\KBD0010".helloworld RETURN VARCHAR2 AS
LANGUAGE JAVA NAME 'Hello.world () return java.lang.string';

Then I attempted to select it with a sql query:

select helloworld()
from dual;

And then I am getting:

ORA-29540: class Hello does not exist