Java Tutorial/Security/Bouncy Castle

Basic class to confirm the Bouncy Castle provider is installed.

import java.security.Security;
public class MainClass {
  public static void main(String[] args) {
    String providerName = "BC";
    if (Security.getProvider(providerName) == null) {
      System.out.println(providerName + " provider not installed");
    } else {
      System.out.println(providerName + " is installed.");
    }
  }
}

Basic demonstration of precedence

import javax.crypto.Cipher;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Cipher cipher = Cipher.getInstance("Blowfish/ECB/NoPadding");
    System.out.println(cipher.getProvider());
    cipher = Cipher.getInstance("Blowfish/ECB/NoPadding", "BC");
    System.out.println(cipher.getProvider());
  }
}