title: NullPointerException when sending ISO8583 request
body: <p>I am trying to send an ISO8583 request to a terminal using the following code:</p>
  
  <pre><code>try {
          XMLParser packager = new XMLParser(this.xmlFile);
  
  
          final ISOMsg isoMsg = new ISOMsg();
          isoMsg.setPackager(packager);
          isoMsg.setMTI("0800");
          isoMsg.set(3, "xxxxxx");
          isoMsg.set(7, "xxxxxxxxxx");    //MMDDhhmmss
          isoMsg.set(11, "xxxxxx");
          isoMsg.set(12, "084500");       //Time of the message HHmmss
          isoMsg.set(13, "0621");         //Date MMDD
          isoMsg.set(41, "xxxxxxxx");
          isoMsg.set(62,"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
          isoMsg.set(63,"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
          BaseChannel channel = new BaseChannel() {};
          channel.setLogger(logger, "server-request-channel");
          channel.setHeader(isoMsg.pack());
          channel.setHost("xx.xx.xx.xx", xxxxx);
          ISOMUX isoMux = new ISOMUX(channel) {
              @Override
              protected String getKey(ISOMsg m) throws ISOException {
                  return super.getKey(m);
              }
          };
  
          isoMux.setLogger(logger, "server-request-mux");
          new Thread(isoMux).start();
          ISORequest req = new ISORequest(isoMsg);
          isoMux.queue(req);
          req.setLogger(logger, "server-request-logger");
          ISOMsg response = req.getResponse(50 * 1000);
  
          if (response != null) {
                  System.out.println("Req ["+ new String(isoMsg.pack()) + "]");
                  System.out.println("Res ["+ new String(response.pack()) + "]");
              }else{
                  System.out.println("Timeout");
              }
          }catch (Exception e) {
              e.printStackTrace();
          }
      }
  </code></pre>
  
  <p>After executing the code,  I get the following exception:</p>
  
  <pre><code>&lt;log realm="server-request-mux" at="Fri Aug 14 00:26:43 WAT 2015.995"&gt;
      &lt;muxreceiver&gt;
          &lt;exception name="null"&gt;
              java.lang.NullPointerException
              at org.jpos.iso.BaseChannel.createISOMsg(BaseChannel.java:561)
              at org.jpos.iso.BaseChannel.createMsg(BaseChannel.java:558)
              at org.jpos.iso.BaseChannel.receive(BaseChannel.java:585)
              at org.jpos.iso.ISOMUX$Receiver.run(ISOMUX.java:263)
              at java.lang.Thread.run(Thread.java:856)
          &lt;/exception&gt;
      &lt;/muxreceiver&gt;
  &lt;/log&gt;
  </code></pre>
  
  <p>I added break point so as to find out the line causing the exception and discovered that the exception occurs whenever it encounters the statement:</p>
  
  <pre><code>ISORequest req = new ISORequest(isoMsg);
  </code></pre>
  
  <p>I am relatively new to ISO8583 jpos financial programming and I want to building an app on android platform.</p>
  
  <p>How do I get over this exception?</p>