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AlgorithmParameterGenerator getInstance() method in Java with Examples

  • Last Updated : 03 Jun, 2021
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getInstance(String algorithm)

The getInstance() method of java.security.AlgorithmParameterGenerator class is used to return an object of AlgorithmParameterGenerator type that implements the specified algorithm.
Syntax: 
 

public static AlgorithmParameterGenerator 
  getInstance(String algorithm)
    throws NoSuchAlgorithmException

Parameters: This method takes the standard name of Algorithm as a parameter.
Return Value: This method returns the new AlgorithmParameterGenerator object.
Exception: This method throws following exception: 
 

  • NoSuchAlgorithmException: if no Provider supports an AlgorithmParameterGeneratorSpi implementation for the specified algorithm.
  • NullPointerException: if the specified algorithm is null.

Below are the examples to illustrate the getInstance() method:
Example 1: 
 

Java




// Java program to demonstrate
// getInstance() method
 
import java.security.*;
import java.util.*;
 
public class GFG1 {
    public static void main(String[] argv)
    {
        try {
            // Getting instance of
            // AlgorithmParameterGenerator
            // By using getInstance() method
            AlgorithmParameterGenerator sr
                = AlgorithmParameterGenerator
                      .getInstance("DSA");
 
            // getting the status of
            // AlgorithmParameterGenerator object
            String str = sr.toString();
 
            // printing the status
            System.out.println("Status: "
                               + str);
        }
 
        catch (NoSuchAlgorithmException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
        catch (NullPointerException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
    }
}
Output: 
Status: java.security.AlgorithmParameterGenerator@232204a1

 

Example 2: To show NoSuchAlgorithmException 
 



Java




// Java program to demonstrate
// getInstance() method
 
import java.security.*;
import java.util.*;
 
public class GFG1 {
    public static void main(String[] argv)
    {
        try {
            // Getting instance of
            // AlgorithmParameterGenerator
            // By using getInstance() method
            AlgorithmParameterGenerator sr
                = AlgorithmParameterGenerator
                      .getInstance("GFG");
 
            // getting the status of
            // AlgorithmParameterGenerator object
            String str = sr.toString();
 
            // printing the status
            System.out.println("Status: " + str);
        }
 
        catch (NoSuchAlgorithmException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
        catch (NullPointerException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
    }
}
Output: 
Exception thrown:
 java.security.NoSuchAlgorithmException:
 GFG AlgorithmParameterGenerator not available

 

Signature getInstance(String algorithm, Provider provider)

The getInstance() method of java.security.AlgorithmParameterGenerator class is used to return a AlgorithmParameterGenerator object that implements the specified signature algorithm and specified provider object.
Syntax: 
 

public static AlgorithmParameterGenerator
  getInstance(String algorithm, Provider provider)
    throws NoSuchAlgorithmException

Parameters: This method takes the following arguments as a parameters: 
 

  • algorithm: which is the name of the algorithm requested.
  • provider: which is the provider specified

Return Value: This method returns the new AlgorithmParameterGenerator object.
Exception: This method throws following exceptions: 
 

  • NoSuchAlgorithmException: if a AlgorithmParameterGeneratorSpi implementation for the specified algorithm is not available from the specified Provider object.
  • IllegalArgumentException: if the provider is null.
  • NullPointerException: if the algorithm is null

Below are the examples to illustrate the getInstance() method:
Example 1:
 

Java




// Java program to demonstrate
// getInstance() method
 
import java.security.*;
import java.util.*;
 
public class GFG1 {
    public static void main(String[] argv)
    {
        try {
            // Getting instance of
            // AlgorithmParameterGenerator
            // By using getInstance() method
            AlgorithmParameterGenerator sr
                = AlgorithmParameterGenerator
                      .getInstance("DSA");
 
            // creating Provider object
            Provider pd = sr.getProvider();
 
            // getting algorithm name
            // by using getAlgorithm() method
            String algo = sr.getAlgorithm();
 
            // Getting instance of
            // AlgorithmParameterGenerator
            // By using getInstance() method
            AlgorithmParameterGenerator sr1
                = AlgorithmParameterGenerator
                      .getInstance(algo, pd);
 
            // getting the status of
            // AlgorithmParameterGenerator object
            String str = sr1.toString();
 
            // printing the status
            System.out.println("Status: "
                               + str);
        }
 
        catch (NoSuchAlgorithmException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
        catch (IllegalArgumentException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
    }
}
Output: 
Status: java.security.AlgorithmParameterGenerator@232204a1

 

Example 2: To show NoSuchAlgorithmException
 

Java




// Java program to demonstrate
// getInstance() method
 
import java.security.*;
import java.util.*;
 
public class GFG1 {
    public static void main(String[] argv)
    {
        try {
            // Getting instance of
            // AlgorithmParameterGenerator
            // By using getInstance() method
            AlgorithmParameterGenerator sr
                = AlgorithmParameterGenerator
                      .getInstance("GFG");
 
            // creating Provider object
            Provider pd = sr.getProvider();
 
            // getting algorithm name
            // by using getAlgorithm() method
            String algo = sr.getAlgorithm();
 
            // Getting instance of
            // AlgorithmParameterGenerator
            // By using getInstance() method
            AlgorithmParameterGenerator sr1
                = AlgorithmParameterGenerator
                      .getInstance(algo, pd);
 
            // getting the status of
            // AlgorithmParameterGenerator object
            String str = sr1.toString();
 
            // printing the status
            System.out.println("Status: " + str);
        }
 
        catch (NoSuchAlgorithmException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
        catch (IllegalArgumentException e) {
 
            System.out.println("Exception thrown: "
                               + e);
        }
    }
}
Output: 
Exception thrown:
 java.security.NoSuchAlgorithmException:
 GFG AlgorithmParameterGenerator not available

 

Reference: 
 

 

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