Java String toLowerCase() with Examples

Java String toLowerCase() method is used and operated over a string where we want to convert all letters to lowercase in a string.

Methods of String toLowerCase()

There are two types of toLowerCase() methods as follows: 

1. toLowerCase()
2. toLowerCase(Locale loc): Converts all the characters into lowercase using the rules of the given Locale.

Note: Internally toLowerCase() works in similar way as toLowerCase(Locale.getDefault()) method.

Syntax of toLowerCase()

public String toLowerCase ()
public String toLowerCase (Locale loc)

The package view of the method is as follows: 

--> java.util Package
    --> String Class
        --> toLowerCase() Method 

Parameters

• Locale value to be applied.

Return Value

• Returns a string in lowercase letter.

Example Java toLowerCase()

Example 1:

java

// Java Program to Demonstrate Working of
// toLowerCase() Method of String Class

// Importing required classes
import java.util.*;

// Main class
class GFG {

    // Main driver method
    public static void main(String args[])
    {

        // Custom input string
        String s = "Geeks for Geeks";

        // Converting string s to lowercase letter
        String s2 = s.toLowerCase();

        // Printing the lowercase string corresponding
        // to input string
        System.out.println(s2);
    }
}

Output

geeks for geeks

Example 2:

java

// Java program to demonstrate Working of toLowerCase()
// Method present inside Locale class

// Importing required classes
import java.util.Locale;

// Main class
class GFG {

    // Main driver method
    public static void main(String args[])
    {
        // Custom input string
        String s = "I Know YOI Bui You Don't Know ME";

        // Locales with the language "tr" for TURKISH
        //"en" for ENGLISH is created
        Locale TURKISH = Locale.forLanguageTag("tr");
        Locale ENGLISH = Locale.forLanguageTag("en");

        // Converting string s to lowercase letter
        // using TURKISH and ENGLISH language
        String gfg2 = s.toLowerCase(TURKISH);
        String gfg3 = s.toLowerCase(ENGLISH);

        // Printing above string
        System.out.println(gfg2);
        System.out.println(gfg3);
    }
}

Output

ı know yoı bui you don't know me
i know yoi bui you don't know me