assertThat(desc.getRawClass(), is(sameClass(Set.class)));
        ParameterizedClassDesc[] args = desc.getArguments();
        assertThat(args.length, is(1));
        assertThat(args[0].getRawClass(), is(sameClass(Integer.class)));

        desc = ParameterizedClassDescFactory.createParameterizedClassDesc(method, 1, map);
        assertThat(desc.getRawClass(), is(sameClass(Map.class)));

            return null;
        }
        final ParameterizedClassDesc pcd = parameterizedClassDesc.getArguments()[0];
        if (pcd == null) {
            return null;
        }
        return pcd.getRawClass();
    }

    @Override
    public Class<?> getKeyClassOfMap() {
        if (!Map.class.isAssignableFrom(fieldType) || !isParameterized()) {
            return null;
        }

            return null;
        }
        final ParameterizedClassDesc pcd = parameterizedClassDescs[index].getArguments()[0];
        if (pcd == null) {
            return null;
        }
        return pcd.getRawClass();
    }

    @Override
    public Class<?> getKeyClassOfMap(final int index) {
        assertArgumentArrayIndex("index", index, parameterTypes.length);

    /**
     * Returns the raw class.
     *
     * @param <T>
     *            the type of the raw class
     * @return the raw class
     * @see ParameterizedType#getRawType()
     */
    <T> Class<T> getRawClass();

    /**
     * Returns an array of {@link ParameterizedClassDesc} representing the type arguments.
     * <p>
     * If the class represented by this instance is not a parameterized class, returns {@literal null}.

    }

    @Override
    public boolean isParameterizedClass() {
        return arguments != null;
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> Class<T> getRawClass() {
        return (Class<T>) rawClass;
    }

    /**
     * Sets the raw class.
     *
     * @param rawClass
     *            The raw class. Must not be {@literal null}.
     */

        assertThat(parameterizedClassDesc, is(notNullValue()));
        assertThat(parameterizedClassDesc.isParameterizedClass(), is(true));
        assertThat(parameterizedClassDesc.getRawClass(), is(sameClass(Class.class)));
        final MyBean myBean = new MyBean();
        aaa.setFieldValue(myBean, String.class);
        assertThat(aaa.getFieldValue(myBean), is(sameClass(String.class)));
    }

    /**