@Override
  public int hashCode() {
    int hash = cachedHash;
    if (hash == 0) {
      hash = 1;
      hash = hash * 31 + className.hashCode();
      for (PdxField field : fields) {
        hash = hash * 31 + field.hashCode();
      }
      if (hash == 0) {
        hash = 1;
      }
      cachedHash = hash;
    }
    return cachedHash;
  }
A count of the total number of variable length field offsets.
geode-core/src/main/java/org/apache/geode/pdx/internal/PdxType.java