Package isSealed(URL) method in Java with Examples

Last Updated : 12 Jul, 2025

The isSealed(URL) method of java.lang.Package class is used to check if this package is sealed or not, with respect to the specified URL. The method returns the result as a boolean value.
Syntax: 
 

public boolean isSealed(URL url)


Parameter: This method does not accept any parameter.
Return Value: This method returns the result as a boolean value.
Below programs demonstrate the isSealed(URL) method.
Example 1:
 

Java 
// Java program to demonstrate
// isSealed(URL) method

import java.net.*;

public class Test {
    public static void main(String[] args)
        throws MalformedURLException
    {

        // returns the Package
        // object for this package
        Package myPackage
            = Package.getPackage("java.lang");

        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());

        URL url
            = new URL("https://www.geeksforgeeks.org");

        // check if this package is sealed or not
        // using isSealed(URL) method
        System.out.println(
            "Is this package sealed or not: "
            + myPackage.isSealed(url));
    }
}

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

 

Example 2:
 

Java 
// Java program to demonstrate
// isSealed(URL) method

import java.net.*;

public class Test {
    public static void main(String[] args)
        throws MalformedURLException
    {

        // returns the Package
        // object for this package
        Package myPackage
            = Package.getPackage("java.io");

        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());

        URL url
            = new URL("http://www.gfg.org");

        // check if this package is sealed or not
        // using isSealed(URL) method
        System.out.println(
            "Is this package sealed or not: "
            + myPackage.isSealed(url));
    }
}

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

 

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

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