code: protected Class<?> getComponentType(GrNode rNode) {
  		// do nothing in this implementation except for primitive arrays
  		// overwritten by subclasses
  		Class<?> compType;
  		if (this.getFieldType().isArray() && (compType = this.getFieldType().getComponentType()).isPrimitive()) {
  			return compType;
  		}
  		return null;
  	}
docs: only called when to check for a concrete simple component type
  @return