How can I sort a List alphabetically?

Advanced sorting techniques

For further flexibility, you could consider custom sorting techniques and duplicate elimination. Let's take a look at some of them.

TreeSet for duplicate elimination

When dealing with unique elements, TreeSet is your friend. It eliminates duplicates while maintaining a sorted order.

Set<String> countries = new TreeSet<>(Arrays.asList("Finland", "Sweden", "Finland", "Norway")); // Oops, got Finland twice! No worries, TreeSet's got our back.
System.out.println(countries); // Outputs: [Finland, Norway, Sweden]
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Streamy business with Java 8

In Java 8 and onwards, Stream.sorted() can be used to create a sorted copy of a list, streamlining sorting like never before.

List<String> sortedCountries = countries.stream()
    .sorted(Comparator.naturalOrder())
    .collect(Collectors.toList());
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Comparator for custom rules

Sometimes sorting isn't as straightforward and calls for custom rules. This is where comparators reign. Here's an example for case-insensitive sorting.

Collections.sort(countries, String.CASE_INSENSITIVE_ORDER); // Capital letters won't weigh more here!
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And if you're sorting international text, a locale-sensitive sorting will ensure accuracy.

Collator collator = Collator.getInstance(Locale.FRANCE);
Collections.sort(countries, collator); // Croissant comes before Baguette, naturellement!
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Dancing with comparators

Understanding comparator logic is like learning the secret handshake of sorting in Java. You can even sort by multiple attributes; for instance, first by length, then alphabetically.

countries.sort(Comparator
                .comparingInt(String::length)
                .thenComparing(Comparator.naturalOrder())); // A little dance between length and alphabetical order
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Remember, the compare() method should mimic equals() to prevent any identity crises.

Performance considerations

Performance is key in deciding the right collection to use. TreeSet often outperforms a List when dealing with uniqueness and sorted order. For those short on pockets filled with processing time, TreeSet can be an ally.

Choosing between sorting methods and collections, remember Batman's wise words – "It's what's inside that counts."

Generic sorting with type safety

Generics are your undefined super heroes, saving you from unwanted runtime surprises. Applying generics in sorting ensures type safety.

List<Country> countries = // ...
countries.sort(Comparator.comparing(Country::getName)); // No country for unsorted men!
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Efficient coding with Java 8

For those who love conciseness, Java 8 offers one-liner sorting.

fruits.sort(Comparator.naturalOrder()); // Look, Ma! Sorting in one line!
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Keeping your comparators consistent

Making sure your compare() method is a law-abiding citizen and yields consistent results is crucial. Remember to do a thorough instanceof check when dealing with polymorphic collections.

Guarding against nulls

Common pitfall alert - sorting lists having null values can unleash the dreaded NullPointerException. Using a null-friendly comparator offers a safety net.

Comparator<String> nullSafeComparator = Comparator
    .nullsFirst(String.CASE_INSENSITIVE_ORDER);
countries.sort(nullSafeComparator); // Null value? No problemo!
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