code: @Nonnull
      public static Jenkins get() throws IllegalStateException {
          Jenkins instance = getInstanceOrNull();
          if (instance == null) {
              throw new IllegalStateException("Jenkins.instance is missing. Read the documentation of Jenkins.getInstanceOrNull to see what you are doing wrong.");
          }
          return instance;
      }
docs: Gets the {@link Jenkins} singleton.
  @return {@link Jenkins} instance
  @throws IllegalStateException for the reasons that {@link #getInstanceOrNull} might return null
  @since 2.98