[SNMP4J] Strange exception

[Frank Fock]

Hi Sasa,

I assume that you are using SNMP4J in a multi-threaded environment.
Then the following patch for org.snmp4j.smi.Variable could solve your
problem:

  private synchronized static void registerSyntaxes() {
    InputStream is = 
Variable.class.getResourceAsStream(SMISYNTAXES_PROPERTIES);
    if (is == null)
      throw new InternalError("Could not read '"+SMISYNTAXES_PROPERTIES+
                              "' from classpath!");
    Properties props = new Properties();
    try {
      props.load(is);
      Hashtable regSyntaxes = new Hashtable(props.size());
      for (Enumeration en = props.propertyNames(); en.hasMoreElements();) {
        String id = (String)en.nextElement();
        String className = props.getProperty(id);
        try {
          Class c = Class.forName(className);
          regSyntaxes.put(new Integer(id), c);
        }
        catch (ClassNotFoundException cnfe) {
          logger.fatal(cnfe);
        }
      }
      // atomic syntax registration
      registeredSyntaxes = regSyntaxes;
    }
    catch (IOException iox) {
      String txt = "Could not read '"+SMISYNTAXES_PROPERTIES+"': "+
                   iox.getMessage();
      logger.fatal(txt);
      throw new InternalError(txt);
    }
  }


An updated SNMP4J release (v1.0.3a) will be available soon from
SNMP4J.org.

Best regards,
Frank

Sasa Markovic wrote:

> Hi,
>
> I have recently discovered SNMP4J and I want to say that this library 
> is much better than any other free SNMP library. I have managed to 
> port my existing java code to SNMP4J very quickly, but from time to 
> time I get the following strange exception:
>
> ==========================================================
>
> java.io.IOException: Encountered unsupported variable syntax: 67
>         at org.snmp4j.smi.Variable.createFromBER(Variable.java:120)
>         at 
> org.snmp4j.smi.VariableBinding.decodeBER(VariableBinding.java:143)
>         at org.snmp4j.PDUv1.decodeBER(PDUv1.java:169)
>         at org.snmp4j.mp.MPv1.prepareDataElements(MPv1.java:170)
>         at 
> org.snmp4j.MessageDispatcherImpl.dispatchMessage(MessageDispatcherImpl.java:204) 
>
>         at 
> org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.java:263) 
>
>         at 
> org.snmp4j.transport.DefaultUdpTransportMapping$ListenThread.run(DefaultUdpTransportMapping.java:172) 
>
> java.io.IOException: Encountered unsupported variable syntax: 67
>         at org.snmp4j.smi.Variable.createFromBER(Variable.java:120)
>         at 
> org.snmp4j.smi.VariableBinding.decodeBER(VariableBinding.java:143)
>         at org.snmp4j.PDUv1.decodeBER(PDUv1.java:169)
>         at org.snmp4j.mp.MPv1.prepareDataElements(MPv1.java:170)
>         at 
> org.snmp4j.MessageDispatcherImpl.dispatchMessage(MessageDispatcherImpl.java:204) 
>
>         at 
> org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.java:263) 
>
>         at 
> org.snmp4j.transport.DefaultUdpTransportMapping$ListenThread.run(DefaultUdpTransportMapping.java:172) 
>
>
> ============================================
>
> I am using PDUv1 to sample some standard OIDs (ifInOctets, ifOutOctets 
> and similar) - nothing more complicated than that. To make things more 
> strange, this exception gets printed on the screen only from time to 
> time - it does not appear on every SNMP request targeting the same OID 
> on the same host. However, my application seems to be working properly 
> but this exception is quite annoying.
>
> Thanx for the help.
>
> Best regards,
> Sasa Markovic
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