KeyFactory getInstance() method in Java with Examples

09 Jun, 2020
The getInstance() method of java.security.KeyFactory class returns a object of KeyFactory type that applys the assigned KeyFactory algorithm.
Syntax:
public static KeyFactory
  getInstance(String algorithm)
  throws NoSuchAlgorithmException
Parameters: This method seeks the standard Algorithm as a parameter whose instance is to be created to this KeyFactory instance.
Return Value: This method returns a new key factory object.
Exception: This method throws following exception:
NoSuchAlgorithmException: if no provider is available to support an key factory spi application for the particular algorithm.
NullPointerException: if algorithm is null.
Below are the examples to illustrate the getInstance() method:
Example 1:
// Java program to demonstrate// getInstance() method  import java.security.*;import java.util.*;  public class GFG1 {    public static void main(String[] argv)    {          try {              // creating the object of KeyFactory            // and getting instance            // By using getInstance() method            KeyFactory sr                = KeyFactory.getInstance("DSA");              // getting the algorithm of KeyFactory object            String str = sr.getAlgorithm();              // printing the status            System.out.println("algorithm : " + str);        }          catch (NoSuchAlgorithmException e) {              System.out.println("Exception thrown : " + e);        }        catch (NullPointerException e) {              System.out.println("Exception thrown : " + e);        }    }}
algorithm : DSA

Example 2: To show NoSuchAlgorithmException
// Java program to demonstrate// getInstance() method  import java.security.*;import java.util.*;  public class GFG1 {    public static void main(String[] argv)    {          try {              // creating the object of KeyFactory            // and getting instance            // By using getInstance() method            KeyFactory sr = KeyFactory.getInstance("GEEKS");              // getting the algorithm of KeyFactory object            String str = sr.getAlgorithm();              // printing the status            System.out.println("algorithm : " + str);        }          catch (NoSuchAlgorithmException e) {              System.out.println("Exception thrown : " + e);        }        catch (NullPointerException e) {              System.out.println("Exception thrown : " + e);        }    }}
Exception thrown :
 java.security.NoSuchAlgorithmException:
 GEEKS KeyFactory not available

The getInstance() method of java.security.KeyFactory class returns a object of KeyFactory type that applys the assigned KeyFactory algorithm and assigned provider object.
Syntax:
public static KeyFactory
  getInstance(String algorithm, String provider)
  throws NoSuchAlgorithmException
Parameters: This method seeks the following arguments as a parameters:
algorithm: which is the name of the algorithm specified to get the instance.
provider: which is the name of the provider to be specified
Return Value: This method returns an new key factory object.
Exception: This method throws following exceptions:
NoSuchAlgorithmException:– if no provider is available to support an key factory spi application for the particular algorithm.
IllegalArgumentException:– if the provider is null.
NullPointerException:– if algorithm is null
Below are the examples to illustrate the getInstance() method:
Example 1:
// Java program to demonstrate// getInstance() method  import java.security.*;import java.util.*;  public class GFG1 {    public static void main(String[] argv)    {        try {            // creating the object of KeyFactory            // and getting instance            // By using getInstance() method            KeyFactory sr                = KeyFactory.getInstance(                    "DSA", "SUN");              // getting the algorithm of KeyFactory object            String str = sr.getAlgorithm();              // printing the status            System.out.println("algorithm : " + str);        }          catch (NoSuchAlgorithmException e) {              System.out.println("Exception thrown : " + e);        }        catch (NullPointerException e) {              System.out.println("Exception thrown : " + e);        }        catch (NoSuchProviderException e) {              System.out.println("Exception thrown : " + e);        }    }}
algorithm : DSA

Example 2: To show NoSuchAlgorithmException
// Java program to demonstrate// getInstance() method  import java.security.*;import java.util.*;  public class GFG1 {    public static void main(String[] argv)    {        try {            // creating the object of KeyFactory            // and getting instance            // By using getInstance() method            KeyFactory sr                = KeyFactory.getInstance(                    "RSA", "SUN");              // getting the algorithm of KeyFactory object            String str = sr.getAlgorithm();              // printing the status            System.out.println("algorithm : " + str);        }          catch (NoSuchAlgorithmException e) {              System.out.println("Exception thrown : " + e);        }        catch (NullPointerException e) {              System.out.println("Exception thrown : " + e);        }        catch (NoSuchProviderException e) {              System.out.println("Exception thrown : " + e);        }    }}
Exception thrown :
 java.security.NoSuchAlgorithmException:
 no such algorithm: RSA for provider SUN

Reference: https://docs.oracle.com/javase/9/docs/api/java/security/KeyFactory.html#getInstance-java.lang.String-
Akanksha_Rai
Java-Functions
Java-KeyFactory
Java-security package
Java
Java
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