Program: 155363
Project: 155363
Buggy source:
public void start(){
  leaseCheckerThread leaseChecker=new leaseCheckerThread();
  leaseChecker.run();
  while (true) {
    byte[] validData;
    DatagramPacket recivedPacket;
    try {
      socket=new DatagramSocket(67);
    }
 catch (    SocketException ex) {
      Logger.getLogger(DHCPServer.class.getName()).log(Level.SEVERE,null,ex);
    }
    DHCPPacket temp=null;
{
      byte[] recievedData=new byte[MaxLength];
      recivedPacket=new DatagramPacket(recievedData,MaxLength);
      try {
        socket.receive(recivedPacket);
      }
 catch (      IOException ex) {
        Logger.getLogger(DHCPServer.class.getName()).log(Level.SEVERE,null,ex);
      }
      validData=Utility.readNByte(recivedPacket.getLength(),recievedData,0);
      recivedPacket.setData(validData);
    }
    temp=new DHCPPacket(recivedPacket);
    Option gatewayOption=new Option((byte)3,(byte)4,gateway.IPAddressToByte());
    temp.getOptions().add(gatewayOption);
    Option DNSOption=new Option((byte)6,(byte)4,DNS.IPAddressToByte());
    temp.getOptions().add(DNSOption);
    Option subnetmaskOption=new Option((byte)1,(byte)4,subnetmask.IPAddressToByte());
    temp.getOptions().add(subnetmaskOption);
    Option serverIPOption=new Option((byte)54,(byte)4,Utility.getIPAddress());
    temp.getOptions().add(serverIPOption);
    Option renewalTimeOption=new Option((byte)58,(byte)4,Utility.intToByteArray(renewal));
    temp.getOptions().add(renewalTimeOption);
    Option rebindingTimeOption=new Option((byte)59,(byte)4,Utility.intToByteArray(rebinding));
    temp.getOptions().add(rebindingTimeOption);
    Option leaseTimeOption=new Option((byte)51,(byte)4,Utility.intToByteArray(lease));
    temp.getOptions().add(leaseTimeOption);
    int optionSize=recivedPacket.getLength() - 240;
    byte[] option=new byte[optionSize];
    option=Utility.readNByte(optionSize,validData,240);
    byte[] messageOption=new byte[6];
    byte[] option50=new byte[6];
    Utility.optionTraverse(option,53,messageOption);
    Utility.optionTraverse(option,50,option50);
    if (messageOption[2] == 1) {
      DHCPPacket offer=Utility.getDiscover(temp,reserved,randomIp,subnetmask);
      Utility.sendReply(offer,socket);
    }
 else     if (messageOption[2] == 3) {
      DHCPPacket AckOrDecline=Utility.getRequest(temp,reserved,db,option50);
      Utility.sendReply(AckOrDecline,socket);
    }
  }
}

Fixed version (ground truth):
public void start(){
  leaseCheckerThread leaseChecker=new leaseCheckerThread();
  leaseChecker.run();
  while (true) {
    byte[] validData;
    DatagramPacket recivedPacket;
    try {
      socket=new DatagramSocket(67);
    }
 catch (    SocketException ex) {
      Logger.getLogger(DHCPServer.class.getName()).log(Level.SEVERE,null,ex);
    }
    DHCPPacket temp=null;
{
      byte[] recievedData=new byte[MaxLength];
      recivedPacket=new DatagramPacket(recievedData,MaxLength);
      try {
        socket.receive(recivedPacket);
      }
 catch (      IOException ex) {
        Logger.getLogger(DHCPServer.class.getName()).log(Level.SEVERE,null,ex);
      }
      validData=Utility.readNByte(recivedPacket.getLength(),recievedData,0);
      recivedPacket.setData(validData);
    }
    temp=new DHCPPacket(recivedPacket);
    Option gatewayOption=new Option((byte)3,(byte)4,gateway.IPAddressToByte());
    temp.getOptions().add(gatewayOption);
    Option DNSOption=new Option((byte)6,(byte)4,DNS.IPAddressToByte());
    temp.getOptions().add(DNSOption);
    Option subnetmaskOption=new Option((byte)1,(byte)4,subnetmask.IPAddressToByte());
    temp.getOptions().add(subnetmaskOption);
    Option serverIPOption=new Option((byte)54,(byte)4,Utility.getIPAddress());
    temp.getOptions().add(serverIPOption);
    Option renewalTimeOption=new Option((byte)58,(byte)4,Utility.intToByteArray(renewal));
    temp.getOptions().add(renewalTimeOption);
    Option rebindingTimeOption=new Option((byte)59,(byte)4,Utility.intToByteArray(rebinding));
    temp.getOptions().add(rebindingTimeOption);
    Option leaseTimeOption=new Option((byte)51,(byte)4,Utility.intToByteArray(lease));
    temp.getOptions().add(leaseTimeOption);
    int optionSize=recivedPacket.getLength() - 240;
    byte[] option=new byte[optionSize];
    option=Utility.readNByte(optionSize,validData,240);
    byte[] messageOption=new byte[6];
    byte[] option50=new byte[6];
    Utility.optionTraverse(option,53,messageOption);
    Utility.optionTraverse(option,50,option50);
    if (messageOption[2] == 1) {
      DHCPPacket offer=Utility.getDiscover(temp,db,reserved,randomIp,subnetmask);
      Utility.sendReply(offer,socket);
    }
 else     if (messageOption[2] == 3) {
      DHCPPacket AckOrDecline=Utility.getRequest(temp,reserved,db,option50);
      Utility.sendReply(AckOrDecline,socket);
    }
  }
}