Assert { public static void notNull(Object param, String paramName) { if (param == null) { String msg = MessageFormat.format( "Parameter ''{0}'' must not be null", paramName); throw new NullPointerException(msg); } } private  Assert(); static void notNull(Object param, String paramName); static void validXMLChars(String s, String paramName); static void isNmtoken(String token, String paramName); static void xliffAttrAvailable(Element elem, String... attrNames); static void xliffAttrRestricted(Element elem,
			boolean nonXliffAllowed, boolean xmlSpaceAllowed,
			boolean xmlLangAllowed, String... xliffAttrNames); static void isXliffElement(org.w3c.dom.Node node); static void isXliffElement(org.w3c.dom.Node node, String name); static void isElement(Node node); static void isNonXliffElement(org.w3c.dom.Node node); static void isInstance(Object object, String name,
			Class<?>... classes); static void areInstances(Collection<?> objects, String name,
			Class<?>... classes);  }
@Test public void testNotNull() { try { Assert.notNull(null, "test"); fail("Expected NullPointerException"); } catch (NullPointerException e) { } Assert.notNull(new Object(), "test"); }