Java String toLowerCase()

The String.toLowerCase() returns a new string after converting all the characters in a given string to lowercase using the Locale rules if specified. Note that the length of the original string and lowercase string may be different due to a few locale-specific characters.

1. String.toLowerCase() API

The toLowerCase() method optionally accepts the Locale instance that should be used for locale-sensitive case conversion. If not specified, the default Locale rules are applied.

public String toLowerCase();

public String toLowerCase(Locale locale);

2. String.toLowerCase() Example

The following Java program converts the string to lowercase using default locale rules. The default Locale is obtained using the Locale.getDefault() method.

String name = "HowToDoInJava.com";

Assertions.assertEquals("howtodoinjava.com", name.toLowerCase());

3. Locale-Specific Case Conversion

Java program to convert the string to lowercase using default locale rules.

System.out.println("hello world".toLowerCase(Locale.getDefault()));
System.out.println("Γειά σου Κόσμε".toLowerCase(Locale.US));

Program output.

hello world
γειά σου κόσμε

In this example, we learned to convert string to lowercase.

Happy Learning !!

References: String Java Doc

Sourcecode on Github