output: #fixed code
                                  @SuppressWarnings("unchecked")
      private static <T extends LwM2mNode> T parseTlv(Tlv[] tlvs, LwM2mPath path, LwM2mModel model, Class<T> nodeClass)
              throws CodecException {
          LOG.trace("Parsing TLV content for path {}: {}", path, tlvs);
  
          // Object
          if (nodeClass == LwM2mObject.class) {
              List<LwM2mObjectInstance> instances = new ArrayList<>();
  
              // is it an array of TLV resources?
              if (tlvs.length > 0 && //
                      (tlvs[0].getType() == TlvType.MULTIPLE_RESOURCE || tlvs[0].getType() == TlvType.RESOURCE_VALUE)) {
  
                  ObjectModel oModel = model.getObjectModel(path.getObjectId());
                  if (oModel == null) {
                      LOG.warn("No model for object {}. The tlv is decoded assuming this is a single instance object",
                              path.getObjectId());
                      instances.add(parseObjectInstanceTlv(tlvs, path.getObjectId(), 0, model));
                  } else if (!oModel.multiple) {
                      instances.add(parseObjectInstanceTlv(tlvs, path.getObjectId(), 0, model));
                  } else {
                      throw new CodecException(String
                              .format("Object instance TLV is mandatory for multiple instances object [path:%s]", path));
                  }
  
              } else {
                  for (Tlv tlv : tlvs) {
                      if (tlv.getType() != TlvType.OBJECT_INSTANCE)
                          throw new CodecException(
                                  String.format("Expected TLV of type OBJECT_INSTANCE but was %s  [path:%s]",
                                          tlv.getType().name(), path));
  
                      instances.add(parseObjectInstanceTlv(tlv.getChildren(), path.getObjectId(),
                              tlv.getIdentifier(), model));
                  }
              }
              return (T) new LwM2mObject(path.getObjectId(), instances);
          }
  
          // Object instance
          else if (nodeClass == LwM2mObjectInstance.class) {
  
              if (tlvs.length == 1 && tlvs[0].getType() == TlvType.OBJECT_INSTANCE) {
                  if (path.isObjectInstance() && tlvs[0].getIdentifier() != path.getObjectInstanceId()) {
                      throw new CodecException(String.format("Id conflict between path [%s] and instance TLV [%d]", path,
                              tlvs[0].getIdentifier()));
                  }
                  // object instance TLV
                  return (T) parseObjectInstanceTlv(tlvs[0].getChildren(), path.getObjectId(), tlvs[0].getIdentifier(),
                          model);
              } else {
                  // array of TLV resources
                  // try to retrieve the instanceId from the path or the model
                  Integer instanceId = path.getObjectInstanceId();
                  if (instanceId == null) {
                      // single instance object?
                      ObjectModel oModel = model.getObjectModel(path.getObjectId());
                      if (oModel != null && !oModel.multiple) {
                          instanceId = 0;
                      } else {
                          instanceId = LwM2mObjectInstance.UNDEFINED;
                      }
                  }
                  return (T) parseObjectInstanceTlv(tlvs, path.getObjectId(), instanceId, model);
              }
          }
  
          // Resource
          else if (nodeClass == LwM2mResource.class) {
              ResourceModel resourceModel = model.getResourceModel(path.getObjectId(), path.getResourceId());
              if (tlvs.length == 0 && resourceModel != null && !resourceModel.multiple) {
                  // If there is no TlV value and we know that this resource is a single resource we raise an exception
                  // else we consider this is a multi-instance resource
                  throw new CodecException(String.format("TLV payload is mandatory for single resource %s", path));
  
              } else if (tlvs.length == 1 && tlvs[0].getType() != TlvType.RESOURCE_INSTANCE) {
                  if (path.isResource() && path.getResourceId() != tlvs[0].getIdentifier()) {
                      throw new CodecException(String.format("Id conflict between path [%s] and resource TLV [%s]", path,
                              tlvs[0].getIdentifier()));
                  }
                  return (T) parseResourceTlv(tlvs[0], path.getObjectId(), path.getObjectInstanceId(), model);
              } else {
                  Type expectedRscType = getResourceType(path, model);
                  return (T) LwM2mMultipleResource.newResource(path.getResourceId(),
                          parseTlvValues(tlvs, expectedRscType, path), expectedRscType);
              }
          } else {
              throw new IllegalArgumentException("invalid node class: " + nodeClass);
          }
  
      }
input: #vulnerable code 
                                  @SuppressWarnings("unchecked")
      private static <T extends LwM2mNode> T parseTlv(Tlv[] tlvs, LwM2mPath path, LwM2mModel model, Class<T> nodeClass)
              throws CodecException {
          LOG.trace("Parsing TLV content for path {}: {}", path, tlvs);
  
          // Object
          if (nodeClass == LwM2mObject.class) {
              List<LwM2mObjectInstance> instances = new ArrayList<>();
  
              // is it an array of TLV resources?
              if (tlvs.length > 0 && //
                      (tlvs[0].getType() == TlvType.MULTIPLE_RESOURCE || tlvs[0].getType() == TlvType.RESOURCE_VALUE)) {
  
                  ObjectModel oModel = model.getObjectModel(path.getObjectId());
                  if (oModel == null) {
                      LOG.warn("No model for object {}. The tlv is decoded assuming this is a single instance object",
                              path.getObjectId());
                      instances.add(parseObjectInstanceTlv(tlvs, path.getObjectId(), 0, model));
                  } else if (!oModel.multiple) {
                      instances.add(parseObjectInstanceTlv(tlvs, path.getObjectId(), 0, model));
                  } else {
                      throw new CodecException(String
                              .format("Object instance TLV is mandatory for multiple instances object [path:%s]", path));
                  }
  
              } else {
                  for (Tlv tlv : tlvs) {
                      if (tlv.getType() != TlvType.OBJECT_INSTANCE)
                          throw new CodecException(
                                  String.format("Expected TLV of type OBJECT_INSTANCE but was %s  [path:%s]",
                                          tlv.getType().name(), path));
  
                      instances.add(parseObjectInstanceTlv(tlv.getChildren(), path.getObjectId(),
                              tlv.getIdentifier(), model));
                  }
              }
              return (T) new LwM2mObject(path.getObjectId(), instances);
          }
  
          // Object instance
          else if (nodeClass == LwM2mObjectInstance.class) {
  
              if (tlvs.length == 1 && tlvs[0].getType() == TlvType.OBJECT_INSTANCE) {
                  if (path.isObjectInstance() && tlvs[0].getIdentifier() != path.getObjectInstanceId()) {
                      throw new CodecException(String.format("Id conflict between path [%s] and instance TLV [%d]", path,
                              tlvs[0].getIdentifier()));
                  }
                  // object instance TLV
                  return (T) parseObjectInstanceTlv(tlvs[0].getChildren(), path.getObjectId(), tlvs[0].getIdentifier(),
                          model);
              } else {
                  // array of TLV resources
                  // try to retrieve the instanceId from the path or the model
                  Integer instanceId = path.getObjectInstanceId();
                  if (instanceId == null) {
                      // single instance object?
                      ObjectModel oModel = model.getObjectModel(path.getObjectId());
                      if (oModel != null && !oModel.multiple) {
                          instanceId = 0;
                      } else {
                          instanceId = LwM2mObjectInstance.UNDEFINED;
                      }
                  }
                  return (T) parseObjectInstanceTlv(tlvs, path.getObjectId(), instanceId, model);
              }
          }
  
          // Resource
          else if (nodeClass == LwM2mResource.class) {
  
              if (tlvs.length == 1 && tlvs[0].getType() != TlvType.RESOURCE_INSTANCE) {
                  if (path.isResource() && path.getResourceId() != tlvs[0].getIdentifier()) {
                      throw new CodecException(String.format("Id conflict between path [%s] and resource TLV [%s]", path,
                              tlvs[0].getIdentifier()));
                  }
                  return (T) parseResourceTlv(tlvs[0], path.getObjectId(), path.getObjectInstanceId(), model);
              } else {
                  Type expectedRscType = getResourceType(path, model);
                  return (T) LwM2mMultipleResource.newResource(path.getResourceId(),
                          parseTlvValues(tlvs, expectedRscType, path), expectedRscType);
              }
          } else {
              throw new IllegalArgumentException("invalid node class: " + nodeClass);
          }
  
      } 
                              #location 76 
                              #vulnerability type NULL_DEREFERENCE