Writing trap listener using netsnmpj for net-snmp apis

Question

I wanted to write a trap listener using netsnmpj.
Could anybody help me regarding this.

Answer 1

The following is the code for trap listener which i took from the example provided in the netsnmpj
I am new to coding as well as to this forum so i am little bit confused.
public class TrapListener {
static OID sysDescrOID ;
static class MyListener implements NetSNMPAction {
public synchronized boolean actionPerformed(int result, NetSNMPSession sess, PDU rcvPdu, Object o) {
System.out.println("Received Trap");
ASNValue val = rcvPdu.findValue(sysDescrOID) ;
this.notify() ;
if( result == NetSNMP.STAT_TIMEOUT ) {
System.err.println("Timeout no response") ;
return false ; // don't call other registered listeners
System.out.println("got sysDescr = " + val) ;
return true ; // continue to call other registered listeners
public static void main(String[] args) throws MIBItemNotFound, NetSNMPSendError, IllegalStateException, InterruptedException {
NetSNMPSession sess ;
NetSNMPAction myListener = new MyListener() ;
String host, community ;
host = "<IP>:162" ;
community = "public" ;
* Open a session to the agent
     sess = new NetSNMPSession(host, community) ;
//sess = new NetSNMPSession();
System.out.println("The NetSNMPSession is : "+sess);
//sess.setSNMPVersion(NetSNMP.SNMPv2c);
sess.setSNMPVersion(NetSNMP.SNMPv1);
          sess.setCommunity(community) ;
     sess.setPeerName(host) ;
                    sess.addListener(myListener) ;
try {
sess.open() ;
catch( IllegalStateException e ) {
System.err.println("caught " + e + " " + host ) ;
System.out.println("SNMP Version is : "+sess.getSnmpVersion());
sysDescrOID = new DefaultOID("SNMPv2-MIB::sysDescr.0") ;
     //PDU pdu = new PDU(NetSNMP.MSG_GET) ;
//pdu.addNullEntry(sysDescrOID) ;
synchronized( myListener ) {
                         //sess.send(pdu, null) ;
System.out.println("Waiting for the Trap");
                         myListener.wait() ;
System.out.println("Waiting for the Trap 1");
                    } // synchronized
}