Code to get Resource Resolver from System User

package com.adobe.aem.guides.wknd.core.services.impl;

import com.adobe.aem.guides.wknd.core.services.ResourceResolverService;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.HashMap;
import java.util.Map;

@Component(service = ResourceResolverService.class)
public class ResourceResolverServiceImpl implements ResourceResolverService {

    @Reference
    private ResourceResolverFactory resourceResolverFactory;
    private static final Logger LOGGER = LoggerFactory.getLogger(ResourceResolverServiceImpl.class);

    @Override
    public ResourceResolver getResourceResolverForSystemUser() {
        ResourceResolver resourceResolver = null;
        try {
            String systemUserName = "wknd-admin-user";

            // Create a map of service user properties
            Map<String, Object> serviceUserProps = new HashMap<>();
            serviceUserProps.put(ResourceResolverFactory.SUBSERVICE, systemUserName);

            // Get the resource resolver using the ResourceResolverFactory
            resourceResolver = resourceResolverFactory.getServiceResourceResolver(serviceUserProps);
        }  catch (Exception e) {
        // Log the exception to understand the failure reason
            LOGGER.error("Error obtaining resource resolver", e);
    }
        return resourceResolver;
    }
}

Update Code for the Service to get Resource Resolver

package com.adobe.aem.guides.wknd.core.services.impl;

import com.adobe.aem.guides.wknd.core.beans.ArticleListDataBean;
import com.adobe.aem.guides.wknd.core.services.ArticleListService;
import com.adobe.aem.guides.wknd.core.services.ResourceResolverService;
import com.day.cq.search.PredicateGroup;
import com.day.cq.search.Query;
import com.day.cq.search.QueryBuilder;
import com.day.cq.search.result.Hit;
import com.day.cq.search.result.SearchResult;
import com.day.cq.wcm.api.Page;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.jcr.RepositoryException;
import javax.jcr.Session;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Component(service = ArticleListService.class)
public class ArticleListServiceImpl implements ArticleListService {

    private static final Logger LOGGER = LoggerFactory.getLogger(ArticleListServiceImpl.class);

    @Reference
    private QueryBuilder builder;

    @Reference
    private ResourceResolverService resourceResolverService;

    @Override
    public List<ArticleListDataBean> getArticleListDataBeans(Resource resource, String articleRootPath) {
        List<ArticleListDataBean> articleListDataBeans = new ArrayList<>();
        ResourceResolver resourceResolver = resourceResolverService.getResourceResolverForSystemUser();

        Map<String, String> predicate = new HashMap<>();
        predicate.put("path", articleRootPath);
        predicate.put("type", "cq:Page");

        try {
            Query query = builder.createQuery(PredicateGroup.create(predicate), resourceResolver.adaptTo(Session.class));
            SearchResult searchResult = query.getResult();

            for (Hit hit : searchResult.getHits()) {
                String path = hit.getPath();
                Resource articleResource = resourceResolver.getResource(path);
                Page articlePage = articleResource != null ? articleResource.adaptTo(Page.class) : null;

                if (articlePage != null) {
                    ArticleListDataBean articleListDataBean = new ArticleListDataBean();
                    articleListDataBean.setPath(path);
                    articleListDataBean.setTitle(articlePage.getTitle());
                    articleListDataBean.setDescription(articlePage.getDescription());

                    articleListDataBeans.add(articleListDataBean);
                }
            }
        } catch (RepositoryException e) {
            LOGGER.error("Error processing search result hit: {}", e.getMessage(), e);
        } catch (Exception e) {
            LOGGER.error("Error executing query for path {}: {}", articleRootPath, e.getMessage(), e);
        }
        return articleListDataBeans;
    }
}