Added standalone script 'PrivateMethodAccess.js'

Signed-off-by: Simon Bennetts <psiinon@gmail.com>

Author: psiinon

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this add-on will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+### Added
+- Standalone script 'PrivateMethodAccess.js'
 ### Changed
 - Add cautionary note to help and readme.
 ### Fixed 

standalone/PrivateMethodAccess.js

@@ -0,0 +1,24 @@
+/*
+When writing scripts you may find that you need to access private java methods.
+This script shows how you can do this easily.
+
+WARNING: we do not consider private methods to be part of the code API, so they may
+be changed or removed at any time.
+If you think you have a strong case for making a method public then either:
+
+1. Ask on the ZAP Dev Group: https://groups.google.com/group/zaproxy-develop
+2. Submit a pull request making the change (but be prepared for it to be rejected)
+
+*/
+
+var ExtensionAlert = Java.type(
+  "org.zaproxy.zap.extension.alert.ExtensionAlert"
+);
+var MethodUtils = Java.type("org.apache.commons.lang3.reflect.MethodUtils");
+
+extAlert = control.getExtensionLoader().getExtension(ExtensionAlert);
+
+print(extAlert);
+
+// Note that there are a lot of other methods in MethodUtils, e.g. for passing parameters.
+print(MethodUtils.invokeMethod(extAlert, true, "getAlertPanel"));