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import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Optional;
import java.util.Set;
/**
* Test cases for Rule #7: "Don't use an Optional to wrap any collection type (List, Set, Map).
* Instead, use an empty collection to represent the absence of values.
*/
public class Marks7 {
void illegalInstantiations() {
// :: error: (optional.collection)
Optional<List<String>> ols = Optional.of(new ArrayList<String>());
// :: error: (optional.collection)
Optional<Set<String>> oss = Optional.of(new HashSet<String>());
}
}
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