code: public static JRTIndex instance(Context context) {
          try {
              JRTIndex instance = context.get(JRTIndex.class);
              if (instance == null)
                  context.put(JRTIndex.class, instance = new JRTIndex());
              return instance;
          } catch (IOException e) {
              throw new UncheckedIOException(e);
          }
      }
docs: Get a context-specific instance of a cache.