Java String toLowerCase()

class Main {
  public static void main(String[] args) {
    String str1 = "JAVA PROGRAMMING";

    // convert to lower case letters
    System.out.println(str1.toLowerCase());

  }
}

// Output: java programming

Syntax of toLowerCase()

The syntax of the string toLowerCase() method is:

string.toLowerCase()

Here, string is an object of the String class.

toLowerCase() Parameters

The toLowerCase() method does not take any parameters.

toLowerCase() Return Value

• returns a string with all upper case letters converted to lowercase letters

Example: Java toLowerCase()

class Main {
  public static void main(String[] args) {
    String str1 = "Learn Java";
    String str2 = "Java123";

    // convert to lowercase letters
    System.out.println(str1.toLowerCase());  // "learn java"
    System.out.println(str2.toLowerCase());  // "java123"

  }
}

As you can see from the above example, toLowerCase() converts all uppercase letters to lower case letters.

toLowerCase() With Locale Parameter

The toLowerCase() method can also take a locale as an argument. This allows you to convert characters in a string to lowercase using the given Locale (such as: Turkish, Lithuanian etc.) rules.

Its syntax is:

string.toLowerCase(Locale locale)

If you do not pass the locale parameter, the default locale, Locale.getDefault(), is used.

To learn more, visit Java toLowerCase() With Locale.

To convert all characters in a string to upper case characters, use the Java String toUpperCase() method.