### Question:
WSDLNamespaceContext implements NamespaceContext { public String getNamespaceURI(String prefix) { if (prefix == null) { throw new NullPointerException("Null prefix"); } else if ("wsdl".equalsIgnoreCase(prefix)) { return "http: } else if ("xmime".equalsIgnoreCase(prefix)) { return "http: } else if ("soap".equalsIgnoreCase(prefix)) { return "http: } else if ("xsd".equalsIgnoreCase(prefix)) { return "http: } else if ("xml".equalsIgnoreCase(prefix)) { return XMLConstants.XML_NS_URI; } else { return XMLConstants.NULL_NS_URI; } }  String getNamespaceURI(String prefix); String getPrefix(String uri); Iterator getPrefixes(String uri);  }### Answer:
@Test public void testGetNamespaceURI() { WSDLNamespaceContext context = new WSDLNamespaceContext(); context.getNamespaceURI("wsdl"); context.getNamespaceURI("xmime"); context.getNamespaceURI("xsd"); context.getNamespaceURI("xml"); context.getNamespaceURI("soap"); context.getNamespaceURI("null"); context.getPrefix(null); context.getPrefixes(null); try { context.getNamespaceURI(null); } catch(NullPointerException ex) { } }