The containsAlias() method of java.security.KeyStore class is used to check the presence of the requested alias.
Syntax:
public final boolean containsAlias(String alias) throws KeyStoreException
Parameter: This method seeks the name of the alias as a parameter of String type of which the entry is to be checked.
Return Value: This method returns a Boolean value stating the result.
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 containsAlias() method:
Example 1:
Java
// Java program to demonstrate// containsAlias() methodimport 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); // checking the presence of the aliases // using containsAlias() method boolean status = sr.containsAlias("ftpkey"); // display the result if (status) System.out.println("This aliases is present"); else System.out.println("This aliases is absent"); } 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); } }} |
This aliases is present
Example 2: For KeyStoreException
Java
// Java program to demonstrate// containsAlias() methodimport 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); // checking the presence of the aliases // using containsAlias() method boolean status = sr.containsAlias("gfg"); // display the result if (status) System.out.println("This aliases is present"); else System.out.println("This aliases is absent"); } catch (NullPointerException e) { System.out.println("Exception thrown : " + e); } catch (KeyStoreException e) { System.out.println("Exception thrown : " + e); } }} |
Exception thrown : java.security.KeyStoreException: Uninitialized keystore
