@Nullable
  public Sdk findSdk(@Nullable final Sdk modelJdk) {
    for (Map.Entry<Sdk, Sdk> entry : myProjectSdks.entrySet()) {
      Sdk jdk = entry.getKey();
      if (Comparing.equal(entry.getValue(), modelJdk)) {
        return jdk;
      }
    }
    return null;
  }
@Nullable
  public Sdk findSdk(@Nullable final Sdk modelJdk)