est ce que quelqu 'un peut m'expliquer ce code ligne par ligne  
jarrive pas a le comprendre en faite; qu est ce qu il fait exactement

ce code est le suivant
import snmp.*;
import java.util.*;
import java.math.*;
import java.net.*;
 
 
 
public class SNMPSample
{
 
    public static void main(String args[])
    {
 
        try
        {
 
            // create a communications interface to a remote SNMP-capable device;
            // need to provide the remote host's InetAddress and the community
            // name for the device; in addition, need to  supply the version number
            // for the SNMP messages to be sent (the value 0 corresponding to SNMP
            // version 1)
            InetAddress hostAddress = InetAddress.getByName("10.0.1.1" );
            String community = "public";
            int version = 0;    // SNMPv1
 
            SNMPv1CommunicationInterface comInterface = new SNMPv1CommunicationInterface(version, hostAddress, community);
 
 
 
            // now send an SNMP GET request to retrieve the value of the SNMP variable
            // corresponding to OID 1.3.6.1.2.1.1.1.0; this is the OID corresponding to
            // the device identifying string, and the type is thus SNMPOctetString
            String itemID = "1.3.6.1.2.1.1.1.0";
 
            System.out.println("Retrieving value corresponding to OID " + itemID);
 
            // the getMIBEntry method of the communications interface returns an SNMPVarBindList
            // object; this is essentially a Vector of SNMP (OID,value) pairs. In this case, the
            // returned Vector has just one pair inside it.
            SNMPVarBindList newVars = comInterface.getMIBEntry(itemID);
 
            // extract the (OID,value) pair from the SNMPVarBindList; the pair is just a two-element
            // SNMPSequence
            SNMPSequence pair = (SNMPSequence)(newVars.getSNMPObjectAt(0));
 
            // extract the object identifier from the pair; it's the first element in the sequence
            SNMPObjectIdentifier snmpOID = (SNMPObjectIdentifier)pair.getSNMPObjectAt(0);
 
            // extract the corresponding value from the pair; it's the second element in the sequence
            SNMPObject snmpValue = pair.getSNMPObjectAt(1);
 
            // print out the String representation of the retrieved value
            System.out.println("Retrieved value: type " + snmpValue.getClass().getName() + ", value " + snmpValue.toString());
 
            // the retrieved value can be obtained from the SNMPObject using the getValue method;
            // the return type of the method is the generic base class Object, and must be cast to
            // the appropriate actual Java type; in this case, for an SNMPOctetString, the underlying
            // Java type is a byte array[]
            byte[] javaByteArrayValue = (byte[])snmpValue.getValue();
 
 
 
            // now send an SNMP GET request to retrieve the value of the SNMP variable
            // corresponding to OID 1.3.6.1.2.1.1.3.0; this is the OID corresponding to
            // the uptime of the device, and the return type is thus SNMPTimeTicks
            itemID = "1.3.6.1.2.1.1.3.0";
 
            System.out.println("Retrieving value corresponding to OID " + itemID);
 
            // the getMIBEntry method of the communications interface returns an SNMPVarBindList
            // object; this is essentially a Vector of SNMP (OID,value) pairs. In this case, the
            // returned Vector has just one pair inside it.
            newVars = comInterface.getMIBEntry(itemID);
 
            // extract the (OID,value) pair from the SNMPVarBindList; the pair is just a two-element
            // SNMPSequence
            pair = (SNMPSequence)(newVars.getSNMPObjectAt(0));
 
            // extract the object identifier from the pair; it's the first element in the sequence
            snmpOID = (SNMPObjectIdentifier)pair.getSNMPObjectAt(0);
 
            // extract the corresponding value from the pair; it's the second element in the sequence
            snmpValue = pair.getSNMPObjectAt(1);
 
            // print out the String representation of the retrieved value
            System.out.println("Retrieved value: type " + snmpValue.getClass().getName() + ", value " + snmpValue.toString());
 
            // the retrieved value can be obtained from the SNMPObject using the getValue method;
            // the return type of the method is the generic base class Object, and must be cast to
            // the appropriate actual Java type; in this case, for SNMPTimeTicks, which is a subclass
            // of SNMPInteger, the actual type is BigInteger (which permits arbitrarily large values to
            // be represented).
            BigInteger javaIntegerValue = (BigInteger)snmpValue.getValue();
 
 
 
            // now send an SNMP SET request to set the value of the SNMP variable
            // corresponding to OID 1.3.6.1.2.1.1.1.0; this is the OID corresponding to
            // the device identifying string, and the type is thus SNMPOctetString;
            // to set a new value, a string is supplied
            itemID = "1.3.6.1.2.1.1.1.0";
 
            SNMPOctetString newValue = new SNMPOctetString("New device name" );
 
            System.out.println("Setting value corresponding to OID " + itemID);
            System.out.println("New value: " + newValue.toString());
 
            // the setMIBEntry method of the communications interface returns the SNMPVarBindList
            // corresponding to the supplied OID and value
            // This call will probably cause an SNMPSetException to be thrown, since the
            // community name "public" is probably not the read/write password of the device
            newVars = comInterface.setMIBEntry(itemID, newValue);
 
 
 
        }
        catch(Exception e)
        {
            System.out.println("Exception during SNMP operation:  " + e + "\n" );
        }
 
    }