code: public static void premain(String args, Instrumentation inst) {
          GagTransformer transformer = new GagTransformer();
          if (args == null || args.length() == 0) {
              transformer.addAllGenerators();
          } else {
              for (String key : args.split(",")) {
                  transformer.addGeneratorForKey(key);
              }
          }
          inst.addTransformer(transformer);
      }
docs: An instrumentation agent needs to have a premain method.