### Question:
DmElement implements DmNode { @Override public String getStringValue() { throw new UnsupportedOperationException("getStringValue() is not supported by DmElement"); } DmElement(final QName name);  DmElement(final QName name, final List<? extends DmNode> childAxis); @Override List<DmNode> getChildAxis(); @Override QName getName(); @Override String getStringValue();  }### Answer:
@Test(expected = UnsupportedOperationException.class) public void testGetStringValue() { new DmElement(new QName(""), new ArrayList<DmElement>()).getStringValue(); }