ResourceBundle.Control newBundle(String, Locale, String, ClassLoader, boolean) in Java

newBundle(String, Locale, String, ClassLoader, boolean): This method is available in java.util.ResourceBundle.Control class of Java.

Syntax:

ResourceBundle java.util.ResourceBundle.Control.newBundle(String baseName, Locale locale, String format, ClassLoader loader, boolean reload) throws IllegalAccessException, InstantiationException, IOException

This method takes five arguments. This method instantiates a resource bundle for the given bundle name of the given format and locale, using the given class loader if necessary.

Note: This method returns null if there is no resource bundle available for the given parameters.

Parameters: Five parameters are required for this method.

baseName: the base bundle name of the resource bundle, a fully qualified class name.

locale: the locale for which the resource bundle should be instantiated.

format: the resource bundle format to be loaded.

loader: the ClassLoader to use to load the bundle.

reload: the flag to indicate bundle reloading; trueif reloading an expired resource bundle, false otherwise.

Returns: the resource bundle instance,or null if none could be found.

Throws:

1. NullPointerException - if bundleName, locale, format, or loader is null, or if null is returned by toBundleName.

2. IllegalArgumentException - if the format is unknown, or if the resource found for the given parameters contains malformed data.

3. ClassCastException - if the loaded class cannot be cast to ResourceBundle.

4. IllegalAccessException - if the class or its nullary constructor is not accessible.

5. InstantiationException - if the instantiation of a class fails for some other reason.

6. ExceptionInInitializerError - if the initialization provoked by this method fails.

7. SecurityException - If a security manager is present and the creation of new instances is denied.

8. IOException - if an error occurred when reading resources using any I/O operations

Approach 1: When no exception

Java

import java.io.IOException;
import java.util.Locale;
import java.util.ResourceBundle;
import java.util.ResourceBundle.Control;

public class ResourceBundleControlnewBundle {
    public static void main(String[] args) 
   throws IllegalAccessException, 
       InstantiationException, IOException {

        ResourceBundle.Control reControl = 
     ResourceBundle.Control.getControl(Control.FORMAT_DEFAULT);

        String baseName = "Hello", format = "java.properties";
        ClassLoader loader = new ClassLoader() {
        };

        boolean reload = false;
        System.out.println(reControl.newBundle(
       baseName, Locale.US, format, loader, 
                        reload).toString());

    }
}

Output:

java.util.PropertyResourceBundle@47089e5f

Approach 2: NullPointerException

Java

import java.io.IOException;
import java.util.Locale;
import java.util.ResourceBundle;
import java.util.ResourceBundle.Control;

public class ResourceBundleControlnewBundle {
    public static void main(String[] args) 
    throws IllegalAccessException, 
        InstantiationException, IOException {

        ResourceBundle.Control reControl = 
      ResourceBundle.Control.getControl(Control.FORMAT_DEFAULT);

        String baseName = null, format = "java.properties";
        ClassLoader loader = new ClassLoader() {
        };

        boolean reload = false;
        System.out.println(reControl.newBundle(
          baseName, Locale.US, format, loader, 
                               reload).toString());

    }
}

Output:

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "String.length()" because "str" is null
	at java.base/java.lang.AbstractStringBuilder.<init>(AbstractStringBuilder.java:105)
	at java.base/java.lang.StringBuilder.<init>(StringBuilder.java:125)
	at java.base/java.util.ResourceBundle$Control.toBundleName(ResourceBundle.java:3459)
	at java.base/java.util.ResourceBundle$Control.newBundle(ResourceBundle.java:3166)
	

Approach 3: IllegalArgumentException 

Java

import java.io.IOException;
import java.util.Locale;
import java.util.ResourceBundle;
import java.util.ResourceBundle.Control;

public class ResourceBundleControlnewBundle {
    public static void main(String[] args) 
          throws IllegalAccessException, 
       InstantiationException, IOException {

        ResourceBundle.Control reControl = 
     ResourceBundle.Control.getControl(Control.FORMAT_DEFAULT);

        String baseName = "Hello", format = "properties";
        ClassLoader loader = new ClassLoader() {
        };

        boolean reload = false;
        System.out.println(reControl.newBundle(
         baseName, Locale.US, format, loader, 
                     reload).toString());

    }
}

Output:

Exception in thread "main" java.lang.IllegalArgumentException: unknown format: properties
	at java.base/java.util.ResourceBundle$Control.newBundle(ResourceBundle.java:3251)