import java.util.Map; class MissingWarning { static final Map VALID_VALUES_BY_KEY = newExceptionOnNullHashMap( "Invalid key", newEntry("key1", "valA"), // <<--- compiler warning on this line newEntry("key2", "valB"), newEntry("key3", "valC"), newEntry("key4", "valD") ); public static Map newExceptionOnNullHashMap(final String exceptionMessage, Map.Entry... entries) { return null; } public static Map.Entry newEntry(K key, V value) { return null; } }