In this section, we will learn what the String toUpperCase() method is and how to use it in Java.

What is Java String toUpperCase() Method?

The `toUpperCase()` method is used to turn all the letters of a string value into uppercase and return a new String object as a result.

Note: this method does not change the original string value but returns a new one as a result.

Java toUpperCase() Method Syntax:

public String toUpperCase()

toUpperCase() Method Parameters:

This method does not take an argument.

toUpperCase() Method Return Value:

The return value of this method is a new string value with the same content as the target string value but converted in uppercase letters.

toUpperCase() Method Exceptions:

This method does not throw an exception.

Example: using String toUpperCase() method

public class Simple {

    public static void main(String[] args)  {
        String s1 = "be kind to one another";
        String res = s1.toUpperCase();
        System.out.println(res);
    }
}

Output:

BE KIND TO ONE ANOTHER

Convert Uppercase to Lowercase

On the contrary, to the `toUpperCase()` method we have `toLowerCase()` method.

This method is used to convert an uppercase string value into lowercase.

Example: converting uppercase string value to lowercase

public class Simple {

    public static void main(String[] args)  {
        String s1 = "BE KIND TO ONE ANOTHER";
        String res = s1.toLowerCase();
        System.out.println(res);
    }
}

Output:

be kind to one another