public void initializeIdentityFields(String... identityFields) {
    this.identityFields = new HashSet<>();
    for (String identityField : identityFields) {
      this.identityFields.add(identityField);
    }
  }
This class is intermediate class to create PdxInstance.
geode-core/src/main/java/org/apache/geode/pdx/internal/json/PdxInstanceSortedHelper.java