class PdfDictionary extends PdfObject {

    public void remove(final PdfName key) {
        hashMap.remove(key);
    }

}

class PdfDictionaryTest {

    @Test
    public void pdfDictionaryRemoveDoesNothingIfKeyIsNull() {

        PdfDictionary dictionary = new PdfDictionary();

        dictionary.remove(null);
    }

}