#vulnerable code 
                                @SuppressWarnings("unchecked")
    private DriverHandler getDriverHandler(ExtensionContext extensionContext,
            Parameter parameter, Class<?> type, Integer index,
            Class<?> constructorClass, boolean isRemote)
            throws InstantiationException, IllegalAccessException,
            InvocationTargetException, NoSuchMethodException {
        DriverHandler driverHandler;
        String contextId = extensionContext.getUniqueId();
        if (isRemote && !browserListMap.isEmpty()) {
            List<Browser> browserListFromContextId = (List<Browser>) getValueFromContextId(
                    browserListMap, contextId);
            driverHandler = (DriverHandler) constructorClass
                    .getDeclaredConstructor(Parameter.class,
                            ExtensionContext.class, Browser.class)
                    .newInstance(parameter, extensionContext,
                            browserListFromContextId.get(index));

        } else if (constructorClass.equals(OtherDriverHandler.class)
                && !browserListMap.isEmpty()) {
            driverHandler = (DriverHandler) constructorClass
                    .getDeclaredConstructor(Parameter.class,
                            ExtensionContext.class, Class.class)
                    .newInstance(parameter, extensionContext, type);

        } else {
            driverHandler = (DriverHandler) constructorClass
                    .getDeclaredConstructor(Parameter.class,
                            ExtensionContext.class)
                    .newInstance(parameter, extensionContext);

        }
        return driverHandler;
    } 
                            #location 16 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @SuppressWarnings("unchecked")
    private DriverHandler getDriverHandler(ExtensionContext extensionContext,
            Parameter parameter, Class<?> type, Integer index,
            Class<?> constructorClass, boolean isRemote)
            throws InstantiationException, IllegalAccessException,
            InvocationTargetException, NoSuchMethodException {
        DriverHandler driverHandler = null;
        String contextId = extensionContext.getUniqueId();
        if (isRemote && !browserListMap.isEmpty()) {
            List<Browser> browserListFromContextId = (List<Browser>) getValueFromContextId(
                    browserListMap, contextId);
            if (browserListFromContextId == null) {
                log.warn("Browser list for context id {} not found", contextId);
            } else {
                driverHandler = (DriverHandler) constructorClass
                        .getDeclaredConstructor(Parameter.class,
                                ExtensionContext.class, Browser.class)
                        .newInstance(parameter, extensionContext,
                                browserListFromContextId.get(index));
            }

        } else if (constructorClass.equals(OtherDriverHandler.class)
                && !browserListMap.isEmpty()) {
            driverHandler = (DriverHandler) constructorClass
                    .getDeclaredConstructor(Parameter.class,
                            ExtensionContext.class, Class.class)
                    .newInstance(parameter, extensionContext, type);

        } else {
            driverHandler = (DriverHandler) constructorClass
                    .getDeclaredConstructor(Parameter.class,
                            ExtensionContext.class)
                    .newInstance(parameter, extensionContext);

        }
        return driverHandler;
    }