title: jPOS logger :To add logger in packager
body: <p>I am implementing ATM Simulator, which accepts ISO8583 msg from client and unpack it using jPOS library.
  Error that has occured while unpacking my msg is : "error unpacking field 102: negativearraysizeexception" .
  I researched about this error and thought about adding logger to my program so that on printing, i would get the information on which data is going into which field.<br>
  Code that i include in my existing java application is as follows :</p>
  
  <pre><code>Logger logger = new Logger();
  logger.addListener (new SimpleLogListener(System.out));
  ((LogSource)p).setLogger(logger, "debug");// p is my ISOPackger
  </code></pre>
  
  <p>It is giving me compilation error as<br>
  1- Constructor Logger() is undefined</p>
  
  <p>2- Method addListener is undefined for type Logger</p>
  
  <p>3- LogSource cannot be resolved to a type</p>
  
  <p>Help me in solving these errors. Any help would be appreciated. Thanks in advance.</p>