Comparing strings by their alphabetical order

What are compareTo & compareToIgnoreCase?

The methods compareTo and compareToIgnoreCase are string comparison mechanisms in Java. compareTo compares strings lexicographically, whereas compareToIgnoreCase does so while ignoring case differences.

When choosing which to use, consider their return values:

• Negative: first string is less than the second.
• Zero: both strings are equal.
• Positive: first string is greater than the second.

Customized sorting with Collator

For sensitive locale-based comparisons, Collator is your go-to. It considers specific language rules and is useful for international applications requiring natural language sorting.

Collator collator = Collator.getInstance(Locale.US);
collator.setStrength(Collator.PRIMARY); // Case and accents don't worry us here
String c = "café";
String d = "cafe";
// Whether your coffee is local or international, we got you covered ☕
System.out.println(collator.compare(c, d));
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JDK 8 and JRE 8 supported locales is a handy resource for locale settings.

Why the order matters

In some scenarios, you don't get to ignore the order. Think of:

• Sorting user entries for a search function.
• Comparing files for a file organization system.
• Organizing list items for UI presentations.

Common pitfalls & remedies

1. Ignoring case: Use toLowerCase() or toUpperCase() before comparing.
2. Spaces & Punctuation: Use trim() to avoid confusion with invisible characters.
3. Null pointers: Always check for null before comparing.
4. Locale usage: Always ensure correct Locale is used with Collator.

Handling special characters

Java's compareTo is sufficient for English letters. For special characters and diacritics, you can’t do without Collator.

Best Practices

1. Use compareToIgnoreCase: For general disregard of case while sorting.
2. Use Collator: For international applications.
3. Test edge cases: With characters like space, hyphen, etc.
4. Benchmark your solution: Test performance with large data sets.