@Override
  public PdxType getPdxTypeForField(String fieldName, String className) {
    Set<PdxType> pdxTypes = getPdxTypesForClassName(className);
    for (PdxType pdxType : pdxTypes) {
      if (pdxType.getPdxField(fieldName) != null) {
        return pdxType;
      }
    }
    return null;
  }
adds a PdxType for a field to a {@code className => Set<PdxType>} map
geode-core/src/main/java/org/apache/geode/pdx/internal/PeerTypeRegistration.java