Java:
Converting a string to lower case

How to:

The String class in Java has a nifty toLowerCase() method that does the hard work for you. Check out this simple usage:

public class LowerCaseExample {
    public static void main(String[] args) {
        String original = "Java ROCKS!";
        String lowerCased = original.toLowerCase();
        System.out.println(lowerCased);
    }
}

Output:

java rocks!

That’s it. The string gets its volume turned down to a chilled-out lowercase.

Deep Dive

Once upon a time, handling text was a tricky business. Different languages, different cases, computer systems screaming in confusion. Java, arriving on the scene in the ’90s, sought to make things easier. The toLowerCase() method has been part of Java’s String class since the early days.

But there’s some cool stuff under the hood. You might wonder why toLowerCase() is even necessary. The thing is, not all cultures define “lower case” the same way. The method is locale-sensitive, using your system’s default locale, or you can specify one using toLowerCase(Locale locale).

Here’s another twist: languages with more ornate scripts, like Turkish, have special “dotless” i characters that could throw a regular lower-casing out the window. Hence, Java provides the option to be meticulous with character conversions.

Alternatives? Sure, you could romp through the string with a for loop, swapping chars manually. But why reinvent the wheel when Java’s got you covered?

Also, this might surprise some: strings in Java are immutable. When you toLowerCase(), you’re not modifying the original string, you’re creating a fresh new one, vest and all.

See Also

Check out these resources to up your string game:

• Java String API:
• Java Locale Class:
• Unicode Case Mappings:

And for the gritty details on the Unicode Standard:

• The Unicode Consortium: