ActionScript 3Understanding the "Error 1009: Cannot access a property or method of a null object reference"


Introduction

An error 1009 is a general error that arises when you are trying to receive a value out of a variable or property that has a value of null. The examples provided expose various cases where this error arises, together with some recommendations on how to mitigate the error.

Remarks

The dreaded and often asked "Error 1009: Cannot access a property or method of a null object reference" is a signal that some of the data appears null, but is tried to be used as a populated object. There are pretty many types of issues that can cause this behavior, and each one should be tested against the code where the error arised.