#vulnerable code 
                                @Override
    public List<OperationArgument> buildResolverArguments(ArgumentBuilderParams params) {
        Method resolverMethod = params.getResolverMethod();
        List<OperationArgument> operationArguments = new ArrayList<>(resolverMethod.getParameterCount());
        AnnotatedType[] parameterTypes = ClassUtils.getParameterTypes(resolverMethod, params.getDeclaringType());
        for (int i = 0; i < resolverMethod.getParameterCount(); i++) {
            Parameter parameter = resolverMethod.getParameters()[i];
            if (parameter.isSynthetic() || parameter.isImplicit()) continue;
            AnnotatedType parameterType;
            try {
                parameterType = params.getTypeTransformer().transform(parameterTypes[i]);
            } catch (TypeMappingException e) {
                throw new TypeMappingException(resolverMethod, parameter, e);
            }
            parameterType = ClassUtils.addAnnotations(parameterType, parameter.getAnnotations());
            operationArguments.add(buildResolverArgument(parameter, parameterType, params.getInclusionStrategy(), params.getEnvironment()));
        }
        return operationArguments;
    } 
                            #location 16 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public List<OperationArgument> buildResolverArguments(ArgumentBuilderParams params) {
        Method resolverMethod = params.getResolverMethod();
        List<OperationArgument> operationArguments = new ArrayList<>(resolverMethod.getParameterCount());
        AnnotatedType[] parameterTypes = ClassUtils.getParameterTypes(resolverMethod, params.getDeclaringType());
        for (int i = 0; i < resolverMethod.getParameterCount(); i++) {
            Parameter parameter = resolverMethod.getParameters()[i];
            if (parameter.isSynthetic() || parameter.isImplicit()) continue;
            AnnotatedType parameterType;
            try {
                parameterType = params.getTypeTransformer().transform(parameterTypes[i]);
            } catch (TypeMappingException e) {
                throw new TypeMappingException(resolverMethod, parameter, e);
            }
            operationArguments.add(buildResolverArgument(parameter, parameterType, params.getInclusionStrategy(), params.getEnvironment()));
        }
        return operationArguments;
    }