code: String getBuildVersion() {
          if (this.buildVersion == null) {
              Properties prop = new Properties();
              try {
                  // try system
                  URL u = ClassLoader.getSystemResource(SQLG_APPLICATION_PROPERTIES);
                  if (u == null) {
                      // try own class loader
                      u = getClass().getClassLoader().getResource(SQLG_APPLICATION_PROPERTIES);
                  }
                  if (u != null) {
                      try (InputStream is = u.openStream()) {
                          prop.load(is);
                      }
                      this.buildVersion = prop.getProperty(APPLICATION_VERSION);
                  }
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
          }
          return this.buildVersion;
      }
docs: get the build version
  
  @return the build version, or null if unknown