code: public void checkMandatoryProperties() throws PdbConfigurationException {
          StringBuilder exceptionMessage = new StringBuilder();
          if (StringUtils.isBlank(getJdbc())) {
              exceptionMessage.append("- A connection string should be declared under the 'database.jdbc' property.\n");
          }
  
          if (StringUtils.isBlank(getEngine())) {
              exceptionMessage.append("- An engine string should be declared under the 'database.engine' property.\n");
          }
  
          if (exceptionMessage.length() > 0) {
              throw new PdbConfigurationException("The following configuration errors were detected in the configuration file: \n"
                      + exceptionMessage.toString());
          }
      }
docs: Checks if the configuration validates for mandatory properties.
  
  @throws PdbConfigurationException If mandatory fields are not set.