// In IntelliJ IDEA Ultimate 14.1.4, with Java8,
// the editor incorrectly highlights various parts of this code as uncompilable, when it is actually fine.
public void testIt()
{
	Map<Integer, String> innerMap = new HashMap<>();
	innerMap.put(2, "abc");
	Map<Long, Map<Integer, String>> outerMap = new HashMap<>();
	outerMap.put(1L, innerMap);
	Map<Long, Map<Integer, String>> transformedMap = outerMap.entrySet().stream()
			.collect(toMap(
					Map.Entry::getKey,
					m -> m.getValue().entrySet().stream()
							.collect(toMap(
									Map.Entry::getKey,
									v -> v.getValue().toUpperCase()))));
}