#fixed code
                                protected void configure(Map config, T instance) throws Exception {
        final Set<Attribute> attributes = describe();

        for (Attribute attribute : attributes) {
            final String name = attribute.getName();
            final Object sub = removeIgnoreCase(config, name);
            if (sub != null) {
                final Class k = attribute.getType();
                final Configurator configurator = Configurator.lookup(k);
                if (configurator == null) throw new IllegalStateException("No configurator implementation to manage "+k);
                if (attribute.isMultiple()) {
                    List values = new ArrayList<>();
                    for (Object o : (List) sub) {
                        Object value = configurator.configure(o);
                        values.add(value);
                    }
                    attribute.setValue(instance, values);
                } else {
                    Object value = configurator.configure(sub);
                    attribute.setValue(instance, value);
                }
            }
        }
        if (!config.isEmpty()) {
            final String invalid = StringUtils.join(config.keySet(), ',');
            throw new IllegalArgumentException("Invalid configuration elements for type " + instance.getClass() + " : " + invalid);
        }
    }
#vulnerable code 
                                protected void configure(Map config, T instance) throws Exception {
        final Set<Attribute> attributes = describe();

        for (Attribute attribute : attributes) {
            final String name = attribute.getName();
            final Object sub = removeIgnoreCase(config, name);
            if (sub != null) {
                if (attribute.isMultiple()) {
                    List values = new ArrayList<>();
                    for (Object o : (List) sub) {
                        Object value = Configurator.lookup(attribute.getType()).configure(o);
                        values.add(value);
                    }
                    attribute.setValue(instance, values);
                } else {
                    Object value = Configurator.lookup(attribute.getType()).configure(sub);
                    attribute.setValue(instance, value);
                }
            }
        }
        if (!config.isEmpty()) {
            final String invalid = StringUtils.join(config.keySet(), ',');
            throw new IllegalArgumentException("Invalid configuration elements for type " + instance.getClass() + " : " + invalid);
        }
    } 
                            #location 16 
                            #vulnerability type NULL_DEREFERENCE