code: public static Optional<String> getStringAsOptWithClasspath(
              String classpath, String charsetName) {
          return getResourceInputStreamAsOpt(classpath)
                  .map(resourceInputStream -> JMInputStream
                          .toString(resourceInputStream, charsetName));
      }
docs: Gets string as opt with classpath.
  
  @param classpath   the classpath
  @param charsetName the charset name
  @return the string as opt with classpath