KeyStore getCertificateChain() method in Java with Examples

The getCertificateChain() method of java.security.KeyStore class is used to provide the certificate chain for the requested alias. . Syntax:

public final Certificate[]
  getCertificateChain(String alias)
  throws KeyStoreException

Parameter: This method accepts a parameter alias which is the name of the alias. Return Value: This method returns the certificate chain for the requested alias if it exists. Exception: This method throws KeyStoreException if you don’t initialize this keystore. Note: All the programs in this article won’t run on online IDE as no ‘privatekey’ Keystore exists. You can check this code on the Java compiler on your system. To check this code, create a Keystore ‘privatekey’ on your system and set your own keystore password to access that keystore. Below are the examples to illustrate the getCertificateChain() method: Example 1:

Java

// Java program to demonstrate
// getCertificateChain() method

import java.security.*;
import java.security.cert.*;
import java.util.*;
import java.io.*;

public class GFG {
    public static void main(String[] argv)
    {

        try {

            // creating the object of KeyStore
            // and getting instance
            // By using getInstance() method
            KeyStore sr = KeyStore.getInstance("JKS");

            // Keystore password is required
            // to access Keystore
            char[] pass = ("123456").toCharArray();

            // creating and initializing
            // object of InputStream
            InputStream is
                = new FileInputStream(
                    "f:/java/private key.store");

            // initializing keystore object
            sr.load(is, pass);

            // getting the certificate
            // using getCertificateChain() method
            Certificate[] certchain
                = sr.getCertificateChain("ftpkey");

            // display the result
            System.out.println(
                "Type of certificate at index 0 : "
                + certchain[0].getType());
        }

        catch (Exception e) {

            System.out.println(e);
        }
    }
}

Output:

Type of certificate at index 0 : X.509

Example 2: For KeyStoreException

Java

// Java program to demonstrate
// getCertificateChain() method

import java.security.*;
import java.security.cert.*;
import java.util.*;
import java.io.*;

public class GFG {
    public static void main(String[] argv)
    {
        try {

            // creating the object of KeyStore
            // and getting instance
            // By using getInstance() method
            KeyStore sr
                = KeyStore.getInstance("JKS");

            // initializing keystore object
            // sr.load(is, pass);

            // getting the certificate
            // using getCertificateChain() method
            Certificate[] certchain
                = sr.getCertificateChain("ftpkey");

            // display the result
            System.out.println(
                "Type of certificate at index 0 : "
                + certchain[0].getType());
        }
        catch (Exception e) {

            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

Exception thrown :
 java.security.KeyStoreException:
 Uninitialized keystore

Reference: https://docs.oracle.com/javase/9/docs/api/java/security/KeyStore.html#getCertificateChain-java.lang.String-