private void startInstantiator(Attributes atts) {
    int id = parseInt(atts.getValue(ID));
    stack.push(id);
  }
When an <code>instantiator</code> element is first encountered, we need to hang on to the id
attribute for use in registration in the end tag function.
geode-core/src/main/java/org/apache/geode/internal/cache/xmlcache/CacheXmlParser.java