Java String toUpperCase() Method

The Java String toUpperCase() method of the String class has converted all characters of the string into an uppercase letter. There is two variant of toUpperCase() method. The key thing that is to be taken into consideration is toUpperCase() method worked the same as to UpperCase(Locale.getDefault()) method as internally default locale is used. In this article, we will learn about String toUpperCase() Method in Java.

Syntax of toUpperCase Java

public String toUpperCase()

Return Type: It returns the string in uppercase letters.

Example of String toUpperCase() Method in Java

Below is the implementation of the String toUpperCase() Method in Java:

java

// Java Program to Demonstrate Working of
// toUpperCase() method

// Main class
class GFG {

    // Main driver method
    public static void main(String args[])
    {
        // Custom input string
        String str = "Welcome! to Geeksforgeeks";

        // Converting above input string to
        // uppercase letters using UpperCase() method
        String strup = str.toUpperCase();

        // Print the uppercased string
        System.out.println(strup);
    }
}

Output

WELCOME! TO GEEKSFORGEEKS

Note: Lowercase is done using the rules of the given Locale.

Java String toUpperCase(Locale locale)

The toUpperCase(Locale locale) method returns a new String object which is the original string in upper case with respect to the Locale method parameter. 

Syntax String toUpperCase() Method in Java

public String toUpperCase(Locale loc)

Parameters:

• Type 1: Locale value to be applied as it converts all the characters into
• Type 2: NA

Example of Java String toUpperCase(Locale locale)

Below is the Implementation of the above method:

java

// Java program to demonstrate Working of toUpperCase()
// method of Locale class

// Importing Locale class from java.util package
import java.util.Locale;

// Main class
class GFG {

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

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

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

        // Converting string str to uppercase letter
        // using TURKISH and ENGLISH language
        String strup1 = str.toUpperCase(TURKISH);
        String strup2 = str.toUpperCase(ENGLISH);
        System.out.println(strup1);
        System.out.println(strup2);
    }
}

Output

GEEKS FOR GEEKS
GEEKS FOR GEEKS