Currently, javac accepts uses of the conditional operator which are in violation of the Java Language Specification:

String[] sa = null;
List<String> ls = (sa == null) ? Arrays.asList(sa) : Collections.emptyList();

According to the spec, the type of the conditional operator should be lub(List<String>, List<Object>) = List<?> why the assignment is illegal. However, javac compiles this example without any errors or warnings.