can the cause of memory leak be detected here?

[Aparna Ram]

hello all,
I've been facing an outofmemory error for a quite a long time now and since I'm also new to Java, I have been unsuccessful in tracing the leak.
I have herewith posted the code that has been giving me the problems.
It sure is a longg code..Can you please patiently go through the code to point me out where the references have not been released, or what other mistakes have been done and thereby guide me with it?
Sorry for the trouble and thanks a million in advance.

SnmpRequest.java
----------------

package cfmanager;
 
import java.io.IOException;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.util.Vector;
 
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.snmp4j.CommandResponder;
import org.snmp4j.CommandResponderEvent;
import org.snmp4j.CommunityTarget;
import org.snmp4j.MessageDispatcher;
import org.snmp4j.MessageDispatcherImpl;
import org.snmp4j.MessageException;
import org.snmp4j.PDU;
import org.snmp4j.PDUv1;
import org.snmp4j.ScopedPDU;
import org.snmp4j.Snmp;
import org.snmp4j.Target;
import org.snmp4j.UserTarget;
import org.snmp4j.asn1.BER;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.log.Log4jLogFactory;
import org.snmp4j.log.LogFactory;
import org.snmp4j.mp.CounterSupport;
import org.snmp4j.mp.DefaultCounterListener;
import org.snmp4j.mp.MPv1;
import org.snmp4j.mp.MPv2c;
import org.snmp4j.mp.MPv3;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.mp.StateReference;
import org.snmp4j.mp.StatusInformation;
import org.snmp4j.security.AuthMD5;
import org.snmp4j.security.AuthSHA;
import org.snmp4j.security.PrivAES128;
import org.snmp4j.security.PrivAES192;
import org.snmp4j.security.PrivAES256;
import org.snmp4j.security.PrivDES;
import org.snmp4j.security.SecurityLevel;
import org.snmp4j.security.SecurityModels;
import org.snmp4j.security.SecurityProtocols;
import org.snmp4j.security.USM;
import org.snmp4j.security.UsmUser;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.Counter32;
import org.snmp4j.smi.Integer32;
import org.snmp4j.smi.IpAddress;
import org.snmp4j.smi.Null;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.SMIConstants;
import org.snmp4j.smi.TcpAddress;
import org.snmp4j.smi.TimeTicks;
import org.snmp4j.smi.UdpAddress;
import org.snmp4j.smi.UnsignedInteger32;
import org.snmp4j.smi.Variable;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.AbstractTransportMapping;
import org.snmp4j.transport.DefaultTcpTransportMapping;
import org.snmp4j.transport.DefaultUdpTransportMapping;
import org.snmp4j.util.MultiThreadedMessageDispatcher;
import org.snmp4j.util.PDUFactory;
import org.snmp4j.util.TableEvent;
import org.snmp4j.util.TableListener;
import org.snmp4j.util.TableUtils;
import org.snmp4j.util.ThreadPool;
 
/**
 * The SnmpRequest application is an example implementation of most of the
 * SNMP4J features. It can be used to send SNMP requests to a target or to
 * listen for traps/notifications and inform requests.
 *
 * @author Frank Fock
 * @version 1.0.3
 * @since 1.0
 */
public class SnmpRequest extends Thread implements CommandResponder, PDUFactory {
    
    // initialize Log4J logging
    static {
        LogFactory.setLogFactory(new Log4jLogFactory());
        BER.setCheckSequenceLength(false);
    }
    
    public static final int DEFAULT = x;
    
    public static final int WALK = x;
    
    public static final int LISTEN = x;
    
    public static final int TABLE = x;
    
    public static final int CVS_TABLE = x;
    
    public static final int TIME_BASED_CVS_TABLE = x;
    
    Target target;
    
    Address address;
    
    OID authProtocol;
    
    OID privProtocol;
    
    OctetString privPassphrase;
    
    OctetString authPassphrase;
    
    OctetString community = new OctetString("xxxxx");
    
    OctetString authoritativeEngineID;
    
    OctetString contextEngineID;
    
    OctetString contextName = new OctetString();
    
    OctetString securityName = new OctetString();
    
    TimeTicks sysUpTime = new TimeTicks(0);
    
    OID trapOID = SnmpConstants.coldStart;
    
    PDUv1 v1TrapPDU = new PDUv1();
    
    int version = SnmpConstants.version3;
    
    int retries = x;
    
    int timeout = xxxx;
    
    int pduType = PDU.GETNEXT;
    
    int maxRepetitions = xx;
    
    int nonRepeaters = x;
    
    Vector vbs = new Vector();
    
    protected int operation = DEFAULT;
    
    int numDispatcherThreads = x;
    
    boolean useDenseTableOperation = false;
    
    // table options
    OID lowerBoundIndex, upperBoundIndex;
    
    public SnmpRequest(String[] args) {
        // Set the default counter listener to return proper USM and MP error
        // counters.
        CounterSupport.getInstance().addCounterListener(
                new DefaultCounterListener());
        
        vbs.add(new VariableBinding(new OID("xxx")));
        int paramStart = parseArgs(args);
        if (paramStart >= args.length) {
            printUsage();
            System.exit(1);
        } else {
            checkOptions();
            address = getAddress(args[paramStart++]);
            Vector vbs = getVariableBindings(args, paramStart);
            checkTrapVariables(vbs);
            if (vbs.size() > 0) {
                this.vbs = vbs;
            }
        }
    }
    
    public int getPduType() {
        return pduType;
    }
    
    public int getVersion() {
        return version;
    }
    
    public Vector getVbs() {
        return vbs;
    }
    
    public boolean isUseDenseTableOperation() {
        return useDenseTableOperation;
    }
    
    public OID getUpperBoundIndex() {
        return upperBoundIndex;
    }
    
    public OID getTrapOID() {
        return trapOID;
    }
    
    public int getTimeout() {
        return timeout;
    }
    
    public Target getTarget() {
        return target;
    }
    
    public TimeTicks getSysUpTime() {
        return sysUpTime;
    }
    
    public OctetString getSecurityName() {
        return securityName;
    }
    
    public int getRetries() {
        return retries;
    }
    
    public OID getPrivProtocol() {
        return privProtocol;
    }
    
    public OctetString getPrivPassphrase() {
        return privPassphrase;
    }
    
    public int getOperation() {
        return operation;
    }
    
    public int getNumDispatcherThreads() {
        return numDispatcherThreads;
    }
    
    public int getNonRepeaters() {
        return nonRepeaters;
    }
    
    public int getMaxRepetitions() {
        return maxRepetitions;
    }
    
    public OID getLowerBoundIndex() {
        return lowerBoundIndex;
    }
    
    public OctetString getContextName() {
        return contextName;
    }
    
    public OctetString getContextEngineID() {
        return contextEngineID;
    }
    
    public OctetString getCommunity() {
        return community;
    }
    
    public OctetString getAuthoritativeEngineID() {
        return authoritativeEngineID;
    }
    
    public OID getAuthProtocol() {
        return authProtocol;
    }
    
    public OctetString getAuthPassphrase() {
        return authPassphrase;
    }
    
    public Address getAddress() {
        return address;
    }
    
    private void checkOptions() {
        if ((operation == WALK)
        && ((pduType != PDU.GETBULK) && (pduType != PDU.GETNEXT))) {
            throw new IllegalArgumentException(
                    "Walk operation is not supported for PDU type: "
                    + PDU.getTypeString(pduType));
        } else if ((operation == WALK) && (vbs.size() != 1)) {
            throw new IllegalArgumentException(
                    "There must be exactly one OID supplied for walk operations");
        }
        if ((pduType == PDU.V1TRAP) && (version != SnmpConstants.version1)) {
            throw new IllegalArgumentException(
                    "V1TRAP PDU type is only available for SNMP version 1");
        }
    }
    
    private void checkTrapVariables(Vector vbs) {
        if ((pduType == PDU.INFORM) || (pduType == PDU.TRAP)) {
            if ((vbs.size() == 0)
            || ((vbs.size() > 1) && (!((VariableBinding) vbs.get(0))
            .getOid().equals(SnmpConstants.sysUpTime)))) {
                vbs.add(0, new VariableBinding(SnmpConstants.sysUpTime,
                        sysUpTime));
            }
            if ((vbs.size() == 1)
            || ((vbs.size() > 2) && (!((VariableBinding) vbs.get(1))
            .getOid().equals(SnmpConstants.snmpTrapOID)))) {
                vbs.add(1, new VariableBinding(SnmpConstants.snmpTrapOID,
                        trapOID));
            }
        }
    }
    
    public synchronized void listen() throws IOException {
        AbstractTransportMapping transport;
        if (address instanceof TcpAddress) {
            transport = new DefaultTcpTransportMapping((TcpAddress) address);
        } else {
            transport = new DefaultUdpTransportMapping((UdpAddress) address);
        }
        ThreadPool threadPool = ThreadPool.create("DispatcherPool",
                numDispatcherThreads);
        MessageDispatcher mtDispatcher = new MultiThreadedMessageDispatcher(
                threadPool, new MessageDispatcherImpl());
        
        // add message processing models
        mtDispatcher.addMessageProcessingModel(new MPv1());
        mtDispatcher.addMessageProcessingModel(new MPv2c());
        mtDispatcher.addMessageProcessingModel(new MPv3());
        
        // add all security protocols
        SecurityProtocols.getInstance().addDefaultProtocols();
        
        Snmp snmp = new Snmp(mtDispatcher, transport);
        if (version == SnmpConstants.version3) {
            USM usm = new USM(SecurityProtocols.getInstance(), new OctetString(
                    MPv3.createLocalEngineID()), 0);
            SecurityModels.getInstance().addSecurityModel(usm);
            if (authoritativeEngineID != null) {
                snmp.setLocalEngine(authoritativeEngineID.getValue(), 0, 0);
            }
            // Add the configured user to the USM
            addUsmUser(snmp);
        } else {
            CommunityTarget target = new CommunityTarget();
            target.setCommunity(community);
            this.target = target;
        }
        
        snmp.addCommandResponder(this);
        
        transport.listen();
        System.out.println("Listening on " + address);
        
        try {
            this.wait();
        } catch (InterruptedException ex) {
        }
    }
    
    private void addUsmUser(Snmp snmp) {
        snmp.getUSM().addUser(
                securityName,
                new UsmUser(securityName, authProtocol, authPassphrase,
                privProtocol, privPassphrase));
    }
    
    private Snmp createSnmpSession() throws IOException {
        AbstractTransportMapping transport;
        if (address instanceof TcpAddress) {
            transport = new DefaultTcpTransportMapping();
        } else {
            transport = new DefaultUdpTransportMapping();
        }
        // Could save some CPU cycles:
        // transport.setAsyncMsgProcessingSupported(false);
        Snmp snmp = new Snmp(transport);
        
        if (version == SnmpConstants.version3) {
            USM usm = new USM(SecurityProtocols.getInstance(), new OctetString(
                    MPv3.createLocalEngineID()), 0);
            SecurityModels.getInstance().addSecurityModel(usm);
            addUsmUser(snmp);
        }
        return snmp;
    }
    
    private Target createTarget() {
        if (version == SnmpConstants.version3) {
            UserTarget target = new UserTarget();
            if (authPassphrase != null) {
                if (privPassphrase != null) {
                    target.setSecurityLevel(SecurityLevel.AUTH_PRIV);
                } else {
                    target.setSecurityLevel(SecurityLevel.AUTH_NOPRIV);
                }
            } else {
                target.setSecurityLevel(SecurityLevel.NOAUTH_NOPRIV);
            }
            target.setSecurityName(securityName);
            return target;
        } else {
            CommunityTarget target = new CommunityTarget();
            target.setCommunity(community);
            return target;
        }
    }
    
    public PDU send() throws IOException {
        Snmp snmp = createSnmpSession();
        this.target = createTarget();
        target.setVersion(version);
        target.setAddress(address);
        target.setRetries(retries);
        target.setTimeout(timeout);
        snmp.listen();
        
        PDU request = createPDU(target);
        if (request.getType() == PDU.GETBULK) {
            request.setMaxRepetitions(maxRepetitions);
            request.setNonRepeaters(nonRepeaters);
        }
        for (int i = 0; i < vbs.size(); i++) {
            request.add((VariableBinding) vbs.get(i));
        }
        
        PDU response = null;
        if (operation == WALK) {
            response = walk(snmp, request, target);
        } else {
            ResponseEvent responseEvent;
            long startTime = System.currentTimeMillis();
            responseEvent = snmp.send(request, target);
            if (responseEvent != null) {
                response = responseEvent.getResponse();
                System.out.println("Received response after "
                        + (System.currentTimeMillis() - startTime) + " millis");
            }
        }
        snmp.close();
        return response;
    }
    
    private static PDU walk(Snmp snmp, PDU request, Target target)
    throws IOException {
        request.setNonRepeaters(0);
        OID rootOID = request.get(0).getOid();
        PDU response = null;
        int objects = 0;
        int requests = 0;
        long startTime = System.currentTimeMillis();
        do {
            requests++;
            ResponseEvent responseEvent = snmp.send(request, target);
            response = responseEvent.getResponse();
            if (response != null) {
                objects += response.size();
            }
        } while (!processWalk(response, request, rootOID));
        System.out.println();
        System.out.println("Total requests sent:    " + requests);
        System.out.println("Total objects received: " + objects);
        System.out.println("Total walk time:        "
                + (System.currentTimeMillis() - startTime) + " milliseconds");
        return response;
    }
    
    private static boolean processWalk(PDU response, PDU request, OID rootOID) {
        if ((response == null) || (response.getErrorStatus() != 0)
        || (response.getType() == PDU.REPORT)) {
            return true;
        }
        boolean finished = false;
        OID lastOID = request.get(0).getOid();
        for (int i = 0; (!finished) && (i < response.size()); i++) {
            VariableBinding vb = response.get(i);
            if ((vb.getOid() == null)
            || (vb.getOid().size() < rootOID.size())
            || (rootOID.leftMostCompare(rootOID.size(), vb.getOid()) != 0)) {
                finished = true;
            } else if (Null.isExceptionSyntax(vb.getVariable().getSyntax())) {
                System.out.println(vb.toString());
                finished = true;
            } else if (vb.getOid().compareTo(lastOID) <= 0) {
                System.out
                        .println("Variable received is not lexicographic successor of requested one:");
                System.out.println(vb.toString() + " <= " + lastOID);
                finished = true;
            } else {
                System.out.println(vb.toString());
                lastOID = vb.getOid();
            }
        }
        if (response.size() == 0) {
            finished = true;
        }
        if (!finished) {
            VariableBinding next = response.get(response.size() - 1);
            next.setVariable(new Null());
            request.set(0, next);
            request.setRequestID(new Integer32(0));
        }
        return finished;
    }
    
    private static Vector getVariableBindings(String[] args, int position) {
        Vector v = new Vector(args.length - position + 1);
        for (int i = position; i < args.length; i++) {
            String oid = args[i];
            char type = 'i';
            String value = null;
            int equal = oid.indexOf("={");
            if (equal > 0) {
                oid = args[i].substring(0, equal);
                type = args[i].charAt(equal + 2);
                value = args[i].substring(args[i].indexOf('}') + 1);
            } else if (oid.indexOf('-') > 0) {
                StringTokenizer st = new StringTokenizer(oid, "-");
                if (st.countTokens() != 2) {
                    throw new IllegalArgumentException(
                            "Illegal OID range specified: '" + oid);
                }
                oid = st.nextToken();
                VariableBinding vbLower = new VariableBinding(new OID(oid));
                v.add(vbLower);
                long last = Long.parseLong(st.nextToken());
                long first = vbLower.getOid().lastUnsigned();
                for (long k = first + 1; k <= last; k++) {
                    OID nextOID = new OID(vbLower.getOid().getValue(), 0,
                            vbLower.getOid().size() - 1);
                    nextOID.appendUnsigned(k);
                    VariableBinding next = new VariableBinding(nextOID);
                    v.add(next);
                }
                continue;
            }
            VariableBinding vb = new VariableBinding(new OID(oid));
            if (value != null) {
                Variable variable;
                switch (type) {
                    case 'i':
                        variable = new Integer32(Integer.parseInt(value));
                        break;
                    case 'u':
                        variable = new UnsignedInteger32(Long.parseLong(value));
                        break;
                    case 's':
                        variable = new OctetString(value);
                        break;
                    case 'x':
                        variable = OctetString.fromString(value, ':', 16);
                        break;
                    case 'd':
                        variable = OctetString.fromString(value, '.', 10);
                        break;
                    case 'b':
                        variable = OctetString.fromString(value, ' ', 2);
                        break;
                    case 'n':
                        variable = new Null();
                        break;
                    case 'o':
                        variable = new OID(value);
                        break;
                    case 't':
                        variable = new TimeTicks(Long.parseLong(value));
                        break;
                    case 'a':
                        variable = new IpAddress(value);
                        break;
                    default:
                        throw new IllegalArgumentException("Variable type " + type
                                + " not supported");
                }
                vb.setVariable(variable);
            }
            v.add(vb);
        }
        return v;
    }
    
    private static Address getAddress(String transportAddress) {
        String transport = "udp";
        int colon = transportAddress.indexOf(':');
        if (colon > 0) {
            transport = transportAddress.substring(0, colon);
            transportAddress = transportAddress.substring(colon + 1);
        }
        // set default port
        if (transportAddress.indexOf('/') < 0) {
            transportAddress += "/161";
        }
        if (transport.equalsIgnoreCase("udp")) {
            return new UdpAddress(transportAddress);
        } else if (transport.equalsIgnoreCase("tcp")) {
            return new TcpAddress(transportAddress);
        }
        throw new IllegalArgumentException("Unknown transport " + transport);
    }
    
    private static String nextOption(String[] args, int position) {
        if (position + 1 >= args.length) {
            throw new IllegalArgumentException("Missing option value for "
                    + args[position]);
        }
        return args[position + 1];
    }
    
    private static OctetString createOctetString(String s) {
        OctetString octetString;
        if (s.startsWith("0x")) {
            octetString = OctetString.fromHexString(s.substring(2), ':');
        } else {
            octetString = new OctetString(s);
        }
        return octetString;
    }
    
    private int parseArgs(String[] args) {
        for (int i = 0; i < args.length; i++) {
            if (args[i].equals("-a")) {
                String s = nextOption(args, i++);
                if (s.equals("MD5")) {
                    authProtocol = AuthMD5.ID;
                } else if (s.equals("SHA")) {
                    authProtocol = AuthSHA.ID;
                } else {
                    throw new IllegalArgumentException(
                            "Authentication protocol unsupported: " + s);
                }
            } else if (args[i].equals("-A")) {
                authPassphrase = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-X") || args[i].equals("-P")) {
                privPassphrase = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-c")) {
                community = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-d")) {
                String debugOption = nextOption(args, i++);
                Logger.getRootLogger().setLevel(Level.toLevel(debugOption));
            } else if (args[i].equals("-e")) {
                authoritativeEngineID = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-E")) {
                contextEngineID = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-h")) {
                printUsage();
                System.exit(0);
            } else if (args[i].equals("-n")) {
                contextName = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-r")) {
                retries = Integer.parseInt(nextOption(args, i++));
            } else if (args[i].equals("-t")) {
                timeout = Integer.parseInt(nextOption(args, i++));
            } else if (args[i].equals("-u")) {
                securityName = createOctetString(nextOption(args, i++));
            } else if (args[i].equals("-V")) {
                printVersion();
                System.exit(0);
            } else if (args[i].equals("-Cr")) {
                maxRepetitions = Integer.parseInt(nextOption(args, i++));
            } else if (args[i].equals("-Cn")) {
                nonRepeaters = Integer.parseInt(nextOption(args, i++));
            } else if (args[i].equals("-Ce")) {
                v1TrapPDU.setEnterprise(new OID(nextOption(args, i++)));
            } else if (args[i].equals("-Ct")) {
                trapOID = new OID(nextOption(args, i++));
            } else if (args[i].equals("-Cg")) {
                v1TrapPDU.setGenericTrap(Integer
                        .parseInt(nextOption(args, i++)));
            } else if (args[i].equals("-Cs")) {
                v1TrapPDU.setSpecificTrap(Integer
                        .parseInt(nextOption(args, i++)));
            } else if (args[i].equals("-Ca")) {
                v1TrapPDU.setAgentAddress(new IpAddress(nextOption(args, i++)));
            } else if (args[i].equals("-Cu")) {
                String upTime = nextOption(args, i++);
                v1TrapPDU.setTimestamp(Long.parseLong(upTime));
                sysUpTime.setValue(Long.parseLong(upTime));
            } else if (args[i].equals("-Ow")) {
                operation = WALK;
            } else if (args[i].equals("-Ol")) {
                operation = LISTEN;
            } else if (args[i].equals("-OtCSV")) {
                operation = CVS_TABLE;
            } else if (args[i].equals("-OttCSV")) {
                operation = TIME_BASED_CVS_TABLE;
            } else if (args[i].equals("-Ot")) {
                operation = TABLE;
            } else if (args[i].equals("-Otd")) {
                operation = TABLE;
                useDenseTableOperation = true;
            } else if (args[i].equals("-Cil")) {
                lowerBoundIndex = new OID(nextOption(args, i++));
            } else if (args[i].equals("-Ciu")) {
                upperBoundIndex = new OID(nextOption(args, i++));
            } else if (args[i].equals("-v")) {
                String v = nextOption(args, i++);
                if (v.equals("1")) {
                    version = SnmpConstants.version1;
                } else if (v.equals("2c")) {
                    version = SnmpConstants.version2c;
                } else if (v.equals("3")) {
                    version = SnmpConstants.version3;
                } else {
                    throw new IllegalArgumentException("Version " + v
                            + " not supported");
                }
            } else if (args[i].equals("-x")) {
                String s = nextOption(args, i++);
                if (s.equals("DES")) {
                    privProtocol = PrivDES.ID;
                } else if ((s.equals("AES128")) || (s.equals("AES"))) {
                    privProtocol = PrivAES128.ID;
                } else if (s.equals("AES192")) {
                    privProtocol = PrivAES192.ID;
                } else if (s.equals("AES256")) {
                    privProtocol = PrivAES256.ID;
                } else {
                    throw new IllegalArgumentException("Privacy protocol " + s
                            + " not supported");
                }
            } else if (args[i].equals("-p")) {
                String s = nextOption(args, i++);
                pduType = PDU.getTypeFromString(s);
                if (pduType == Integer.MIN_VALUE) {
                    throw new IllegalArgumentException("Unknown PDU type " + s);
                }
            } else if (!args[i].startsWith("-")) {
                return i;
            } else {
                throw new IllegalArgumentException("Unknown option " + args[i]);
            }
        }
        return 0;
    }
    
    protected static void printVersion() {
        System.out.println();
        System.out.println("SNMP4J Command Line Tool v1.6 Copyright "
                + (char) 0xA9 + " 2004-2005, Frank Fock and Jochen Katz");
        System.out.println("http://www.snmp4j.org");
        System.out.println();
        System.out.println("SNMP4J is licensed under the Apache License 2.0:");
        System.out.println("http://www.apache.org/licenses/LICENSE-2.0.txt");
        System.out.println();
    }
    
    /**
     * printUsage
     */
    protected static void printUsage() {
        String[] usage = new String[] {
            "",
                    "Usage: SNMP4J [options] [transport:]address [OID[={type}value] ...]",
                    "",
                    "  -a  authProtocol      Sets the authentication protocol used to",
                    "                        authenticate SNMPv3 messages. Valid values are",
                    "                        MD5 and SHA.",
                    "  -A  authPassphrase    Sets the authentication pass phrase for authenticated",
                    "                        SNMPv3 messages.",
                    "  -c  community         Sets the community for SNMPv1/v2c messages.",
                    "  -Ca agentAddress      Sets the agent address field of a V1TRAP PDU.",
                    "                        The default value is '0.0.0.0'.",
                    "  -Cg genericID         Sets the generic ID for SNMPv1 TRAPs (V1TRAP).",
                    "                        The default is 1 (coldStart).",
                    "  -Ce enterpriseOID     Sets the enterprise OID field of a V1TRAP PDU.",
                    "  -Cil lowerBoundIndex  Sets the lower bound index for TABLE operations.",
                    "  -Ciu upperBoundIndex  Sets the upper bound index for TABLE operations.",
                    "  -Cn non-repeaters     Sets  the  non-repeaters field for GETBULK PDUs.",
                    "                        It specifies the number of supplied variables that",
                    "                        should not be iterated over. The default is 0.",
                    "  -Cr max-repetitions   Sets the max-repetitions field for GETBULK PDUs.",
                    "                        This specifies the maximum number of iterations",
                    "                        over the repeating variables. The default is 10.",
                    "  -Cs specificID        Sets the specific ID for V1TRAP PDU. The default is 0.",
                    "  -Ct trapOID           Sets the trapOID (1.3.6.1.6.3.1.1.4.1.0) of an INFORM",
                    "                        or TRAP PDU. The default is 1.3.6.1.6.3.1.1.5.1.",
                    "  -Cu upTime            Sets the sysUpTime field of an INFORM, TRAP, or",
                    "                        V1TRAP PDU.",
                    "  -d  debugLevel        Sets the global debug level for Log4J logging output.",
                    "                        Valid values are OFF, ERROR, WARN, INFO, and DEBUG.",
                    "  -e  engineID          Sets the authoritative engine ID of the command",
                    "                        responder used for SNMPv3 request messages. If not",
                    "                        supplied, the engine ID will be discovered.",
                    "  -E  contextEngineID   Sets the context engine ID used for the SNMPv3 scoped",
                    "                        PDU. The authoritative engine ID will be used for the",
                    "                        context engine ID, if the latter is not specified.",
                    "  -h                    Displays this message and then exits the application.",
                    "  -n  contextName       Sets the target context name for SNMPv3 messages. ",
                    "                        Default is the empty string.",
                    "  -Ol                   Activates listen operation mode. In this mode, the",
                    "                        application will listen for incoming TRAPs and INFORMs",
                    "                        on the supplied address. Received request will be",
                    "                        dumped to the console until the application is stopped.",
                    "  -Ot                   Activates table operation mode. In this mode, the",
                    "                        application receives tabular data from the column",
                    "                        OIDs specified as parameters. The retrieved rows will",
                    "                        be dumped to the console ordered by their index values.",
                    "  -Otd                  Activates dense table operation mode. In this mode, the",
                    "                        application receives tabular data from the column",
                    "                        OIDs specified as parameters. The retrieved rows will",
                    "                        be dumped to the console ordered by their index values.",
                    "                        In contrast to -Ot this option must not be used with",
                    "                        sparse tables. ",
                    "  -OtCSV                Same as -Ot except that for each SNMP row received",
                    "                        exactly one row of comma separated values will printed",
                    "                        to the console where the first column contains the row",
                    "                        index.",
                    "  -OttCSV               Same as -OtCSV except that each row's first column",
                    "                        will report the current time (millis after 1.1.1970)",
                    "                        when the request has been sent.",
                    "  -Ow                   Activates walk operation mode for GETNEXT and GETBULK",
                    "                        PDUs. If activated, the GETNEXT and GETBULK operations",
                    "                        will be repeated until all instances within the",
                    "                        OID subtree of the supplied OID have been retrieved",
                    "                        successfully or until an error occurred.",
                    "  -p  pduType           Specifies the PDU type to be used for the message.",
                    "                        Valid types are GET, GETNEXT, GETBULK (SNMPv2c/v3),",
                    "                        SET, INFORM, TRAP, and V1TRAP (SNMPv1).",
                    "  -r  retries           Sets the number of retries used for requests. A zero",
                    "                        value will send out a request exactly once.",
                    "                        Default is 1.",
                    "  -t  timeout           Sets the timeout in milliseconds between retries.",
                    "                        Default is 1000 milliseconds.",
                    "  -u  securityName      Sets the security name for authenticated v3 messages.",
                    "  -v  1|2c|3            Sets the SNMP protocol version to be used.",
                    "                        Default is 3.",
                    "  -V                    Displays version information and then exits.",
                    "  -x  privacyProtocol   Sets the privacy protocol to be used to encrypt",
                    "                        SNMPv3 messages. Valid values are DES, AES (AES128),",
                    "                        AES192, and AES256.",
                    "  -X  privacyPassphrase Sets the privacy pass phrase for encrypted",
                    "                        SNMPv3 messages.",
                    "",
                    "The address of the target SNMP engine is parsed according to the",
                    "specified <transport> selector (default selector is udp):",
                    "",
                    "  udp | tcp             hostname[/port]",
                    "                        ipv4Address[/port]",
                    "                        ipv6Address[/port]",
                    "",
                    "The OIDs have to be specified in numerical form, for example:",
                    "  1.3.6.1.2.1.1.5.0  (which will return the sysName.0 instance with a GET)",
                    "To request multiple instances, add additional OIDs with a space as",
                    "separator. For the last sub-identifier of a plain OID (without an assigned",
                    "value) a range can be specified, for example '1.3.6.1.2.1.2.2.1-10' will",
                    "has the same effect as enumerating all OIDs from '1.3.6.1.2.1.2.2.1' to",
                    "'1.3.6.1.2.1.2.2.10'.",
                    "For SET and INFORM request, you can specify a value for each OID by",
                    "using the following form: OID={type}value where <type> is one of",
                    "the following single characters enclosed by '{' and '}':",
                    "  i                     Integer32",
                    "  u                     UnsingedInteger32, Gauge32",
                    "  s                     OCTET STRING",
                    "  x                     OCTET STRING specified as hex string where",
                    "                        bytes separated by colons (':').",
                    "  d                     OCTET STRING specified as decimal string",
                    "                        where bytes are separated by dots ('.').",
                    "  n                     Null",
                    "  o                     OBJECT IDENTIFIER",
                    "  t                     TimeTicks",
                    "  a                     IpAddress",
                    "  b                     OCTET STRING specified as binary string where",
                    "                        bytes are separated by spaces.",
                    "",
                    "An example for a complete SNMPv2c SET request to set sysName:",
                    " SNMP4J -c private -v 2c -p SET udp:localhost/161 \"1.3.6.1.2.1.1.5.0={s}SNMP4J\"",
                    "",
                    "To walk the whole MIB tree with GETBULK and using SNMPv3 MD5 authentication:",
                    " SNMP4J -a MD5 -A MD5UserAuthPassword -u MD5User -p GETBULK -Ow 127.0.0.1/161",
                    "",
                    "Listen for unauthenticated SNMPv3 INFORMs and TRAPs and all v1/v2c TRAPs:",
                    " SNMP4J -u aSecurityName -Ol 0.0.0.0/162",
                    "",
                    "Send an unauthenticated SNMPv3 notification (trap):",
                    " SNMP4J -p TRAP -v 3 -u aSecurityName 127.0.0.1/162 \"1.3.6.1.2.1.1.3.0={t}0\" \\",
                    "  \"1.3.6.1.6.3.1.1.4.1.0={o}1.3.6.1.6.3.1.1.5.1\" \\",
                    "  \"1.3.6.1.2.1.1.1.0={s}System XYZ, Version N.M\"",
                    "Retrieve rows of the columnar objects ifDescr to ifInOctets and ifOutOctets:",
                    " SNMP4J -c public -v 2c -Ot localhost 1.3.6.1.2.1.2.2.1.2-10\\",
                    "  1.3.6.1.2.1.2.2.1.16", "" };
                    
                    for (int i = 0; i < usage.length; i++) {
                        System.out.println(usage[i]);
                    }
    }
    
    protected static void printVariableBindings(PDU response) {
        for (int i = 0; i < response.size(); i++) {
            VariableBinding vb = response.get(i);
            System.out.println(vb.toString());
        }
    }
    
    protected static void printReport(PDU response) {
        if (response.size() < 1) {
            System.out.println("REPORT PDU does not contain a variable binding.");
            return;
        }
        
        VariableBinding vb = response.get(0);
        OID oid = vb.getOid();
        if (SnmpConstants.usmStatsUnsupportedSecLevels.equals(oid)) {
            System.out.print("REPORT: Unsupported Security Level.");
        } else if (SnmpConstants.usmStatsNotInTimeWindows.equals(oid)) {
            System.out.print("REPORT: Message not within time window.");
        } else if (SnmpConstants.usmStatsUnknownUserNames.equals(oid)) {
            System.out.print("REPORT: Unknown user name.");
        } else if (SnmpConstants.usmStatsUnknownEngineIDs.equals(oid)) {
            System.out.print("REPORT: Unknown engine id.");
        } else if (SnmpConstants.usmStatsWrongDigests.equals(oid)) {
            System.out.print("REPORT: Wrong digest.");
        } else if (SnmpConstants.usmStatsDecryptionErrors.equals(oid)) {
            System.out.print("REPORT: Decryption error.");
        } else if (SnmpConstants.snmpUnknownSecurityModels.equals(oid)) {
            System.out.print("REPORT: Unknown security model.");
        } else if (SnmpConstants.snmpInvalidMsgs.equals(oid)) {
            System.out.print("REPORT: Invalid message.");
        } else if (SnmpConstants.snmpUnknownPDUHandlers.equals(oid)) {
            System.out.print("REPORT: Unknown PDU handler.");
        } else if (SnmpConstants.snmpUnavailableContexts.equals(oid)) {
            System.out.print("REPORT: Unavailable context.");
        } else if (SnmpConstants.snmpUnknownContexts.equals(oid)) {
            System.out.print("REPORT: Unknown context.");
        } else {
            System.out.print("REPORT contains unknown OID (" + oid.toString()
            + ").");
        }
        System.out.println(" Current counter value is "
                + vb.getVariable().toString() + ".");
    }
    
    public synchronized void processPdu(CommandResponderEvent e) {
        PDU command = e.getPDU();
        if (command != null) {
            System.out.println(command.toString());
            if ((command.getType() != PDU.TRAP)
            && (command.getType() != PDU.V1TRAP)
            && (command.getType() != PDU.REPORT)
            && (command.getType() != PDU.RESPONSE)) {
                command.setErrorIndex(0);
                command.setErrorStatus(0);
                command.setType(PDU.RESPONSE);
                StatusInformation statusInformation = new StatusInformation();
                StateReference ref = e.getStateReference();
                try {
                    e.getMessageDispatcher().returnResponsePdu(
                            e.getMessageProcessingModel(),
                            e.getSecurityModel(), e.getSecurityName(),
                            e.getSecurityLevel(), command,
                            e.getMaxSizeResponsePDU(), ref, statusInformation);
                } catch (MessageException ex) {
                    System.err.println("Error while sending response: "
                            + ex.getMessage());
                    Logger.getLogger(SnmpRequest.class).error(ex);
                }
            }
        }
    }
    
    public PDU createPDU(Target target) {
        PDU request;
        if (target.getVersion() == SnmpConstants.version3) {
            request = new ScopedPDU();
            ScopedPDU scopedPDU = (ScopedPDU) request;
            if (contextEngineID != null) {
                scopedPDU.setContextEngineID(contextEngineID);
            }
            if (contextName != null) {
                scopedPDU.setContextName(contextName);
            }
        } else {
            if (pduType == PDU.V1TRAP) {
                request = v1TrapPDU;
            } else {
                request = new PDU();
            }
        }
        request.setType(pduType);
        return request;
    }
    
    public ArrayList table() throws IOException {
        Snmp snmp = createSnmpSession();
        this.target = createTarget();
        target.setVersion(version);
        target.setAddress(address);
        target.setRetries(retries);
        target.setTimeout(timeout);
        snmp.listen();
        
        TableUtils tableUtils = new TableUtils(snmp, this);
        tableUtils.setMaxNumRowsPerPDU(maxRepetitions);
        Counter32 counter = new Counter32();
        ArrayList mac = null;
        
        OID[] columns = new OID[vbs.size()];
        for (int i = 0; i < columns.length; i++) {
            columns[i] = ((VariableBinding) vbs.get(i)).getOid();
        }
        //long startTime = System.currentTimeMillis();
        synchronized (counter) {
            
            SmTableListener listener;
                        /*
                         * TableListener listener; if (operation == TABLE) { listener = new
                         * TextTableListener(); } else { listener = new
                         * CVSTableListener(System.currentTimeMillis()); }
                         */
            listener = new SmTableListener();
            if (useDenseTableOperation) {
                tableUtils.getDenseTable(target, columns, listener, counter,
                        lowerBoundIndex, upperBoundIndex);
            } else {
                tableUtils.getTable(target, columns, listener, counter,
                        lowerBoundIndex, upperBoundIndex);
            }
            try {
                counter.wait(timeout);
            } catch (InterruptedException ex) {
            }
            mac = listener.getMacList();
        }
        
                /*
                 * System.out.println("Table received in " + (System.currentTimeMillis() -
                 * startTime) + " milliseconds.");
                 */
        snmp.close();
        target = null;
        return mac;
    }
    
    class CVSTableListener implements TableListener {
        
        private long requestTime;
        
        public CVSTableListener(long time) {
            this.requestTime = time;
        }
        
        public boolean next(TableEvent event) {
            if (operation == TIME_BASED_CVS_TABLE) {
                System.out.print(requestTime);
                System.out.print(",");
            }
            System.out.print("\"" + event.getIndex() + "\",");
            for (int i = 0; i < event.getColumns().length; i++) {
                Variable v = event.getColumns()[i].getVariable();
                String value = v.toString();
                switch (v.getSyntax()) {
                    case SMIConstants.SYNTAX_OCTET_STRING: {
                        StringBuffer escapedString = new StringBuffer(value
                                .length());
                        StringTokenizer st = new StringTokenizer(value, "\"", true);
                        while (st.hasMoreTokens()) {
                            String token = st.nextToken();
                            escapedString.append(token);
                            if (token.equals("\"")) {
                                escapedString.append("\"");
                            }
                        }
                    }
                    case SMIConstants.SYNTAX_IPADDRESS:
                    case SMIConstants.SYNTAX_OBJECT_IDENTIFIER:
                    case SMIConstants.SYNTAX_OPAQUE: {
                        System.out.print("\"");
                        System.out.print(value);
                        System.out.print("\"");
                        break;
                    }
                    default: {
                        System.out.print(value);
                    }
                }
                if (i + 1 < event.getColumns().length) {
                    System.out.print(",");
                }
            }
            System.out.println();
            return true;
        }
        
        public void finished(TableEvent event) {
            synchronized (event.getUserObject()) {
                event.getUserObject().notify();
            }
        }
    }
    
    class TextTableListener implements TableListener {
        
        public void finished(TableEvent event) {
            System.out.println();
            System.out.println("Table walk completed with status "
                    + event.getStatus() + ". Received " + event.getUserObject()
                    + " rows.");
            synchronized (event.getUserObject()) {
                event.getUserObject().notify();
            }
        }
        
        public boolean next(TableEvent event) {
            System.out.println("MacIndex = " + event.getIndex() + ":");
            for (int i = 0; i < event.getColumns().length; i++) {
                System.out.println(event.getColumns()[i]);
            }
            System.out.println();
            ((Counter32) event.getUserObject()).increment();
            return true;
        }
    }
    
    class SmTableListener implements TableListener {
        
        ArrayList mac = new ArrayList();
        
        public void finished(TableEvent event) {
            synchronized (event.getUserObject()) {
                event.getUserObject().notify();
            }
        }
        
        public boolean next(TableEvent event) {
            mac.add(event.getIndex());
            ((Counter32) event.getUserObject()).increment();
            return true;
        }
        
        public ArrayList getMacList() {
            return mac;
        }
    }
    
        
    public void setAddress(Address address) {
        this.address = address;
    }
    
    public void setVersion(int version) {
        this.version = version;
    }
    
    public void setVbs(Vector vbs) {
        this.vbs = vbs;
    }
    
    public void setUseDenseTableOperation(boolean useDenseTableOperation) {
        this.useDenseTableOperation = useDenseTableOperation;
    }
    
    public void setUpperBoundIndex(OID upperBoundIndex) {
        this.upperBoundIndex = upperBoundIndex;
    }
    
    public void setTrapOID(OID trapOID) {
        this.trapOID = trapOID;
    }
    
    public void setTimeout(int timeout) {
        this.timeout = timeout;
    }
    
    public void setTarget(Target target) {
        this.target = target;
    }
    
    public void setSysUpTime(TimeTicks sysUpTime) {
        this.sysUpTime = sysUpTime;
    }
    
    public void setSecurityName(OctetString securityName) {
        this.securityName = securityName;
    }
    
    public void setRetries(int retries) {
        this.retries = retries;
    }
    
    public void setPrivProtocol(OID privProtocol) {
        this.privProtocol = privProtocol;
    }
    
    public void setPrivPassphrase(OctetString privPassphrase) {
        this.privPassphrase = privPassphrase;
    }
    
    public void setPduType(int pduType) {
        this.pduType = pduType;
    }
    
    public void setOperation(int operation) {
        this.operation = operation;
    }
    
    public void setNumDispatcherThreads(int numDispatcherThreads) {
        this.numDispatcherThreads = numDispatcherThreads;
    }
    
    public void setNonRepeaters(int nonRepeaters) {
        this.nonRepeaters = nonRepeaters;
    }
    
    public void setMaxRepetitions(int maxRepetitions) {
        this.maxRepetitions = maxRepetitions;
    }
    
    public void setLowerBoundIndex(OID lowerBoundIndex) {
        this.lowerBoundIndex = lowerBoundIndex;
    }
    
    public void setContextName(OctetString contextName) {
        this.contextName = contextName;
    }
    
    public void setContextEngineID(OctetString contextEngineID) {
        this.contextEngineID = contextEngineID;
    }
    
    public void setCommunity(OctetString community) {
        this.community = community;
    }
    
    public void setAuthoritativeEngineID(OctetString authoritativeEngineID) {
        this.authoritativeEngineID = authoritativeEngineID;
    }
    
    public void setAuthProtocol(OID authProtocol) {
        this.authProtocol = authProtocol;
    }
    
    public void setAuthPassphrase(OctetString authPassphrase) {
        this.authPassphrase = authPassphrase;
    }
    
}

SnmpThread.java
---------------

package cfmanager;
 
import java.io.IOException;
import java.util.ArrayList;
import java.util.StringTokenizer;
 
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.snmp4j.PDU;
import org.snmp4j.asn1.BER;
import org.snmp4j.log.Log4jLogFactory;
import org.snmp4j.log.LogFactory;
import org.snmp4j.smi.VariableBinding;
import cfmanager.SeamlessMobility;
 

public class SnmpThread extends Thread {
    
    static {
        LogFactory.setLogFactory(new Log4jLogFactory());
        BER.setCheckSequenceLength(false);
    }
    
    public static final int DEFAULT = x;
    
    public static final int WALK = x;
    
    public static final int LISTEN = x;
    
    public static final int TABLE = x;
    
    public static final int CVS_TABLE = x;
    
    public static final int TIME_BASED_CVS_TABLE = x;
    
    public cfmanager.SeamlessMobility sm;
    
    private boolean current;
    
    private String mac;
    
    SnmpThread(SeamlessMobility sm) {
        this.sm = sm;
        current = false;
        mac = "";
    }
    
    public void check(boolean x, String mac) {
        //System.out.println(x+ ": "+mac);
        if (x) {
            if (!current) {
                current = true;
                this.mac = mac;
                sm.handleSnmpEvent(true, this.mac);
            }
        } else {
            if (current) {
                current = false;
                sm.handleSnmpEvent(false, this.mac);
                this.mac = "";
            }
        }
        sm = null;
    }
    
    public boolean atHome(String mc) {
        if (mc.equalsIgnoreCase("xxxxxxxx")) {
            return current;
        }
        return true;
    }
    
    
    public void run() {
        while (true) {
            onThreadRun();
            try{
                Thread.sleep(1000);
            } catch (InterruptedException e) {
            }
        }
    }
    
    public void onThreadRun() {
        ArrayList tmp = askAccessPoint("xx.xx.xx.xxx");
        if (tmp != null) {
            int tmpSize = tmp.size();
            if (tmpSize > 0) {
                for (int i = 0; i < tmpSize; i++) {
                    String mac = tmp.get(0).toString();
                    StringTokenizer st;
                    st = new StringTokenizer(mac, ".");
                    String hex = "";
                    while (st.hasMoreTokens()) {
                        String nextToken = st.nextToken();
                        hex += Integer.toHexString(Integer.parseInt(nextToken));
                    }
                    //System.out.println(hex);
                    check(true, hex);
                }
            } else {
                check(false, "");
            }
        } else {
            check(false, "");
        }
        tmp = null;
    }
    
    public ArrayList askAccessPoint(String apip) {
        
        try {
            if (System.getProperty("log4j.configuration") == null) {
                BasicConfigurator.configure();
            }
            Logger.getRootLogger().setLevel(Level.OFF);
            
            String ssid = "xxx";
            byte[] a = ssid.getBytes();
            
            String oidSsid = Integer.toString(a.length);
            for (int i = 0; i < a.length; i++)
                oidSsid += "." + a[i];
 
            String oid = ".x.x.x.x" + ".x." + oidSsid;// +oidMac+".";
            String community = "xxx";
            String options = "x";
            String cmd = "x " + community + " " + options + " " + apip + " " + oid;
            int cmdLength = cmd.length();
            for (int i = 0; i < cmdLength / 2; i++)
                cmd = cmd.replaceAll("  ", " ");
            
            SnmpRequest snmpRequest;
            snmpRequest = new SnmpRequest(cmd.split(" "));
            try {
                if (snmpRequest.operation == LISTEN) {
                    snmpRequest.listen();
                } else if ((snmpRequest.operation == TABLE)
                || (snmpRequest.operation == CVS_TABLE)
                || (snmpRequest.operation == TIME_BASED_CVS_TABLE)) {
                    return snmpRequest.table();
                } else {
                    PDU response = snmpRequest.send();
                    if ((snmpRequest.getPduType() == PDU.TRAP)
                    || (snmpRequest.getPduType() == PDU.REPORT)
                    || (snmpRequest.getPduType() == PDU.V1TRAP)
                    || (snmpRequest.getPduType() == PDU.RESPONSE)) {
                        System.out.println(PDU.getTypeString(snmpRequest
                                .getPduType())
                                + " sent successfully");
                    } else if (response == null) {
                        System.out.println("Request timed out.");
                    } else if (response.getType() == PDU.REPORT) {
                        snmpRequest.printReport(response);
                    } else if (snmpRequest.operation == DEFAULT) {
                        System.out.println("Response received with requestID="
                                + response.getRequestID() + ", errorIndex="
                                + response.getErrorIndex() + ", "
                                + "errorStatus="
                                + response.getErrorStatusText() + "("
                                + response.getErrorStatus() + ")");
                        snmpRequest.printVariableBindings(response);
                    } else if (snmpRequest.operation == WALK) {
                        System.out.println("End of walked subtree '"
                                + ((VariableBinding) snmpRequest.vbs.get(0))
                                .getOid() + "' reached at:");
                        snmpRequest.printVariableBindings(response);
                    } else {
                        System.out.println("Received something strange: requestID="
                                + response.getRequestID()
                                + ", errorIndex="
                                + response.getErrorIndex()
                                + ", "
                                + "errorStatus="
                                + response.getErrorStatusText()
                                + "("
                                + response.getErrorStatus() + ")");
                        snmpRequest.printVariableBindings(response);
                    }
                }
            } catch (IOException ex) {
                System.err.println("Error while trying to send request: " + ex.getMessage());
                ex.printStackTrace();
            }
            //snmpRequest = null;
        } catch (IllegalArgumentException iaex) {
            System.err.print("Error: " + iaex.getMessage());
            iaex.printStackTrace();
        }
        return null;
    }
}

Thanks for your time and waiting for a reply.
Regards
aparna

[Ilja Preuss]

The best way I know to find a memory leak is to run the code in a profiler which can show the number of instances for each class. Search for classes whichs number of instances increases in unsuspected dimensions.

A good profiler than can also tell you why those instances aren't garbage collected.

[Aparna Ram]

Hi,
Could you then suggest such a profiler which would help me find out why the instances are not getting garbage collected?
I use:
Netbeans 4.1 IDE
jdk_1.4.2
Tomcat 5.0

kindly guide.
TIA
Regards
Aparna

[Ilja Preuss]

We are using JProfiler at work. It's quite good, but not free.

[William Brogden]

I had a memory leak one time due to objects extending Thread being created but not allowed to run. I thought the objects would be GCed because I dropped the reference but it turns out that all objects extending Thread get registered in a ThreadGroup held by the JVM.
I finally detected this by adding a method that would get the ThreadGroup and dump a list of all the held Threads - boy was I surprised

Bill

[Aparna Ram]

Hi,
Thanks for your reply. I now check the number of active threads, it keeps on increasing at a whopping rate.!
Is this causing teh memory leak? How do I proceed now?
How were you able to solve your problem of memory leak?

Kindly guide me through.

Thanks and Regards
Aparna

[William Brogden]

Endlessly increasing number of active Threads can certainly cause a memory leak - it did for me!
My solution was to rewrite the code so that every Thread gets start()ed - but a simple flag is checked in the run method to immediately return ; if the run conditions are not met. The JVM Thread management will take care of disposing of the object extending Thread - assuming you keep no other reference to it - but you have to exit the run() method.
Please let us know how it turns out!
Bill