code: public X509Certificate[] getAcceptedIssuers() {
          try {
              Collection<X509Certificate> trusted = CertificateLoadUtil.getTrustedCertificates(
                      this.parameters.getTrustStore(), null);
              return trusted.toArray(new X509Certificate[trusted.size()]);
          } catch (KeyStoreException e) {
              logger.warn("Unable to load trusted Certificates.  Authentication will fail.",e);
              return new X509Certificate[]{};
          }
      }
docs: Get the collection of trusted certificate issuers.
  
  @return The trusted certificate issuers.