code: public static PublicKey readPublicKey(String pemResName) throws Exception {
          InputStream contentIS = TokenUtils.class.getResourceAsStream(pemResName);
          byte[] tmp = new byte[4096];
          int length = contentIS.read(tmp);
          PublicKey publicKey = decodePublicKey(new String(tmp, 0, length));
          return publicKey;
      }
docs: Read a PEM encoded public key from the classpath
  
  @param pemResName - key file resource name
  @return PublicKey
  @throws Exception on decode failure