code: public ClassDoc[] thrownExceptions() {
          ListBuffer<ClassDocImpl> l = new ListBuffer<>();
          for (Type ex : sym.type.getThrownTypes()) {
              ex = env.types.erasure(ex);
              //### Will these casts succeed in the face of static semantic
              //### errors in the documented code?
              ClassDocImpl cdi = env.getClassDoc((ClassSymbol)ex.tsym);
              if (cdi != null) l.append(cdi);
          }
          return l.toArray(new ClassDocImpl[l.length()]);
      }
docs: Return exceptions this method or constructor throws.
  
  @return an array of ClassDoc[] representing the exceptions
  thrown by this method.