HowToDoInJava

  • Python
  • Java
  • Spring Boot
  • Dark Mode
Home / Java / String / Java String toLowerCase() method example

Java String toLowerCase() method example

The Java String toLowerCase() returns a string which is result of converting all characters in given string to lowercase.

1. String toLowerCase() method

Use String.toLowerCase() converts any string to lowercase letters.

1.1. Method syntax

String toLowerCase() method is overloaded and comes in two variants.

/**
* @param locale - locale use the case transformation rules for given locale
* 
* @return - string converted to lowercase
*/
public String toLowerCase();

public String toLowerCase(Locale locale);

1.2. ‘null’ is not valid method argument

Method does not accept 'null' argument. It will throw NullPointerException in case method argument is null.

Exception in thread "main" java.lang.NullPointerException
	at java.lang.String.toLowerCase(String.java:2710)
	at com.StringExample.main(StringExample.java:11)

2. Java convert string to lowercase example

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

public class StringExample 
{
    public static void main(String[] args) 
    {
        String string = "Hello World";
        
        String lowercaseString = string.toLowerCase();
        
        System.out.println(lowercaseString);
    }
}

Program output.

hello world

toLowerCase() method is equal to calling toLowerCase(Locale.getDefault()).

3. Java String toLowerCase(Locale locale) example

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

public class StringExample 
{
    public static void main(String[] args) 
    {
        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.

References:

A Guide to Java String
String Java Doc

Was this post helpful?

Let us know if you liked the post. That’s the only way we can improve.

Share this:

  • Twitter
  • Facebook
  • LinkedIn
  • Reddit

About Lokesh Gupta

A family guy with fun loving nature. Love computers, programming and solving everyday problems. Find me on Facebook and Twitter.

Comments are closed on this article!

Search Tutorials

String methods

  • String concat()
  • String hashCode()
  • String contains()
  • String compareTo()
  • String compareToIgnoreCase()
  • String equals()
  • String equalsIgnoreCase()
  • String charAt()
  • String indexOf()
  • String lastIndexOf()
  • String intern()
  • String split()
  • String replace()
  • String replaceFirst()
  • String replaceAll()
  • String substring()
  • String startsWith()
  • String endsWith()
  • String toUpperCase()
  • String toLowerCase()

String examples

  • Convert String to int
  • Convert int to String
  • Convert String to long
  • Convert long to String
  • Convert CSV String to List
  • Java StackTrace to String
  • Convert float to String
  • String – Alignment
  • String – Immutable
  • String – StringJoiner
  • Java – Split string
  • String – Escape HTML
  • String – Unescape HTML
  • String – Convert to title case
  • String – Find duplicate words
  • String – Left pad a string
  • String – Right pad a string
  • String – Reverse recursively
  • String – Leading whitespaces
  • String – Trailing whitespaces
  • String – Remove whitespaces
  • String – Reverse words
  • String – Find duplicate characters
  • String – Check empty string
  • String – Get first 4 characters
  • String – Get last 4 characters
  • String – (123) 456-6789 pattern
  • String – Interview Questions

Java Tutorial

  • Java Introduction
  • Java Keywords
  • Java Flow Control
  • Java OOP
  • Java Inner Class
  • Java String
  • Java Enum
  • Java Collections
  • Java ArrayList
  • Java HashMap
  • Java Array
  • Java Sort
  • Java Clone
  • Java Date Time
  • Java Concurrency
  • Java Generics
  • Java Serialization
  • Java Input Output
  • Java New I/O
  • Java Exceptions
  • Java Annotations
  • Java Reflection
  • Java Garbage collection
  • Java JDBC
  • Java Security
  • Java Regex
  • Java Servlets
  • Java XML
  • Java Puzzles
  • Java Examples
  • Java Libraries
  • Java Resources
  • Java 14
  • Java 12
  • Java 11
  • Java 10
  • Java 9
  • Java 8
  • Java 7

Meta Links

  • About Me
  • Contact Us
  • Privacy policy
  • Advertise
  • Guest and Sponsored Posts

Recommended Reading

  • 10 Life Lessons
  • Secure Hash Algorithms
  • How Web Servers work?
  • How Java I/O Works Internally?
  • Best Way to Learn Java
  • Java Best Practices Guide
  • Microservices Tutorial
  • REST API Tutorial
  • How to Start New Blog

Copyright © 2020 · HowToDoInjava.com · All Rights Reserved. | Sitemap

  • Java 15 New Features
  • Sealed Classes and Interfaces
  • EdDSA (Ed25519 / Ed448)