code: private static Signer createSigner(String signerType) {
          Class<? extends Signer> signerClass = SIGNERS.get(signerType);
          Signer signer;
          try {
              signer = signerClass.newInstance();
          } catch (InstantiationException ex) {
              throw new IllegalStateException(
                      "Cannot create an instance of " + signerClass.getName(),
                      ex);
          } catch (IllegalAccessException ex) {
              throw new IllegalStateException(
                      "Cannot create an instance of " + signerClass.getName(),
                      ex);
          }
          return signer;
      }
docs: Create an instance of the given signer.
  
  @param signerType The signer type.
  
  @return The new signer instance.