Empaquetar el método isSealed() en Java con ejemplos

El método isSealed() de la clase java.lang.Package se usa para verificar si este paquete está sellado o no. El método devuelve el resultado como un valor booleano.
Sintaxis: 
 

public boolean isSealed()

Parámetro: Este método no acepta ningún parámetro.
Valor devuelto: este método devuelve el resultado como un valor booleano .
Los siguientes programas muestran el método isSealed().
Ejemplo 1:
 

// Java program to demonstrate
// isSealed() method
 
public class Test {
    public static void main(String[] args)
    {
 
        // returns the Package
        // object for this package
        Package myPackage
            = Package.getPackage("java.lang");
 
        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());
 
        // check if this package is sealed or not
        // using isSealed() method
        System.out.println(
            "Is this package sealed or not: "
            + myPackage.isSealed());
    }
}

Package represented by myPackage: package java.lang, Java Platform API Specification, version 1.8
Is this package sealed or not: false

Ejemplo 2:
 

// Java program to demonstrate
// isSealed() method
 
public class Test {
    public static void main(String[] args)
    {
 
        // returns the Package
        // object for this package
        Package myPackage
            = Package.getPackage("java.io");
 
        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());
 
        // check if this package is sealed or not
        // using isSealed() method
        System.out.println(
            "Is this package sealed or not: "
            + myPackage.isSealed());
    }
}

Package represented by myPackage: package java.io, Java Platform API Specification, version 1.8
Is this package sealed or not: false

Referencia: https://docs.oracle.com/javase/9/docs/api/java/lang/Package.html#isSealed–