#fixed code
                                public NodeAssert hasAttribute(String attributeName, String attributeValue) {
        isNotNull();

        final Map.Entry<QName, String> attribute = attributeForName(attributeName);
        if (attribute == null || !attribute.getValue().equals(attributeValue)) {
            throwAssertionError(shouldHaveAttributeWithValue(actual.getNodeName(), attributeName, attributeValue));
        }

        return this;
    }
#vulnerable code 
                                public NodeAssert hasAttribute(String attributeName, String attributeValue) {
        isNotNull();

        final Map.Entry<QName, String> attribute = requestAttributeForName(attributeName);
        if (!attribute.getValue().equals(attributeValue)) {
            throwAssertionError(shouldHaveAttributeWithValue(actual, attributeName, attributeValue));
        }

        return this;
    } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE