map.put(1, "test");
Entry entryToPut = (Entry)map.entrySet().iterator().next();
Entry testEntry = new AbstractMap.SimpleImmutableEntry(entryToPut);
assertEquals(1,testEntry.getKey());
assertEquals("test",testEntry.getValue());
map.clear();
map.put(null, null);
entryToPut = (Entry)map.entrySet().iterator().next();
testEntry = new AbstractMap.SimpleImmutableEntry(entryToPut);
assertNull(testEntry.getKey());
assertNull(testEntry.getValue());