String toLowerCase()

The toLowerCase() method is a part of the String class and is used to convert all characters of a string to lowercase. This method returns a new string with all characters converted to lowercase while leaving any characters that are already lowercase unchanged.

The basic syntax of the toLowerCase() method is as follows:

String toLowerCase()

Here’s how you can use it:

String original = "Hello World";
String lowercase = original.toLowerCase(); // "hello world"

In this example, the toLowerCase() method is called on the string "Hello World", and it returns a new string with all characters converted to lowercase.

Keep in mind the following:

• The toLowerCase() method doesn’t modify the original string. Instead, it creates a new string with the lowercase representation of the characters.
• This method uses the default locale’s rules for converting characters to lowercase. If you need to perform case conversion according to a specific locale, you can use the overloaded version of this method that accepts a Locale argument:

  String toLowerCase(Locale locale)

For example:

  String original = "Übermensch";
  String lowercase = original.toLowerCase(Locale.GERMAN); // "übermensch"

• Some characters might have multiple lowercase equivalents in different locales. The conversion behavior might differ based on the rules of the locale.

Here are a few more examples:

String str1 = "Java";
String str2 = "LoWerCaSe";
String str3 = "ThIs Is A MixED CaSe StRiNg";

String lowercase1 = str1.toLowerCase();      // "java"
String lowercase2 = str2.toLowerCase();      // "lowercase"
String lowercase3 = str3.toLowerCase();      // "this is a mixed case string"

The toLowerCase() method is particularly useful when you need to perform case-insensitive string comparisons or when you want to ensure consistent case usage in your application, regardless of the input.