KeyStore aliases() method in Java with Examples

The aliases() method of java.security.KeyStore class provides alias name associated with this keystore object. 

Syntax:

public final Enumeration aliases()
  throws KeyStoreException

Return Value: This method returns the list of all alias associated with this keystore object as an Enum object.
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 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 aliases() method:
Example 1:

Java

// Java program to demonstrate
// aliases() 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 MessageDigest
            // and getting instance
            // By using getInstance() method
            KeyStore sr = KeyStore.getInstance("JKS");

            // keystore password is require 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 list of aliases
            // using aliases() method
            Enumeration<String> e = sr.aliases();

            // display the result
            System.out.println("List of all the alias present");
            while (e.hasMoreElements()) {
                System.out.print(e.nextElement() + "");
                System.out.println();
            }
        }

        catch (NoSuchAlgorithmException e) {

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

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

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

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

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

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

Output:

List of all the alias present
ftpkey

Example 2: For 

Java

// Java program to demonstrate
// aliases() 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 MessageDigest
            // and getting instance
            // By using getInstance() method
            KeyStore sr = KeyStore.getInstance("JKS");

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

            // getting the list of aliases
            // using aliases() method
            Enumeration<String> e = sr.aliases();

            // display the result
            System.out.println("List of all the alias present");
            while (e.hasMoreElements()) {
                System.out.print(e.nextElement() + "");
                System.out.println();
            }
        }
        catch (NullPointerException e) {

            System.out.println("Exception thrown : " + e);
        }
        catch (KeyStoreException 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#aliases–