title: IllegalAccessError when calling ant script from maven-antrun-plugin
body: <p>I just updated Maven from 2.0.9 to 2.2.1 and I'm getting the following exception when running a maven build:</p>
  
  <pre>
  INFO] [antrun:run {execution: precompile-jsp}]
  [INFO] Executing tasks
  
  default:
  
  jspc:
      [mkdir] Created dir: C:\builds\trunk\webapps\vyre_portlets\WEB-INF\jsp_src
  [INFO] ------------------------------------------------------------------------
  [ERROR] BUILD ERROR
  [INFO] ------------------------------------------------------------------------
  [INFO] An Ant BuildException has occured: The following error occurred while executing this line:
  C:\unify\trunk\portlets\build-jsps.xml:87: The following error occurred while executing this line:
  C:\unify\trunk\portlets\build-jsps.xml:7: java.lang.IllegalAccessError: tried to access method org.apache.tools.ant.launch.Locator.decodeUri(Ljava/lang/String;)Ljava/lang/String; from class org.apache.tools.ant.AntClassLoader
  </pre>
  
  <p>The build-jsps.xml ant script runs the org.apache.jasper.JspC task to precompile JSP in the a webapp that maven is building. This was working fine with Maven 2.0.9.</p>
  
  <p>Google gives a bunch of people asking similar questions, but no answers. Has anyone run into this and knows how to resolve this? Or even just why I'm getting the IllegalAccessError?</p>