Locale toLanguageTag() Method in Java with Examples

The toLanguageTag() method of Locale class in Java is used to return a well-formed IETF BCP 47 language tag representing this locale object. Now there can be few complications when a language, country or variant does not satisfy the above-mentioned tag which is handled well by this method:

• If the mentioned language does not satisfy the tag, then it will be emitted as Undetermined or “und”.
• If the mentioned country does not satisfy the tag, it will be omitted.
• If the same occurs with the Variant, then each sub-segment is emitted as a subtag.

Syntax:

public String toLanguageTag()

Parameters: This method does not take any parameters.

Return Value: This method returns IETF BCP 47 language tag representation of this locale.

Below programs illustrate the working of toLanguageTag() method:
Program 1:

// Java code to illustrate
// toLanguageTag() method

import java.util.*;

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

        // Creating a new locale
        Locale first_locale
            = new Locale("Germany");

        // Displaying first locale
        System.out.println("Locale: "
                           + first_locale);

        // Displaying the LanguageTag
        System.out.println("The LanguageTag: "
                           + first_locale.toLanguageTag());
    }
}

Output:

Locale: germany
The LanguageTag: germany

Program 2:

// Java code to illustrate
// toLanguageTag() method

import java.util.*;

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

        // Creating a new locale
        Locale first_locale
            = new Locale("en", "USA");

        // Displaying first locale
        System.out.println("Locale: "
                           + first_locale);

        // Displaying the LanguageTag
        System.out.println("The LanguageTag: "
                           + first_locale.toLanguageTag());
    }
}

Output:

Locale: en_USA
The LanguageTag: en

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Locale.html#toLanguageTag()