diff --git a/src/main/java/org/wikitolearn/wikirating/service/RevisionService.java b/src/main/java/org/wikitolearn/wikirating/service/RevisionService.java
index 78742b1..03ccbc8 100644
--- a/src/main/java/org/wikitolearn/wikirating/service/RevisionService.java
+++ b/src/main/java/org/wikitolearn/wikirating/service/RevisionService.java
@@ -1,69 +1,72 @@
 /**
  * 
  */
 package org.wikitolearn.wikirating.service;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.ListIterator;
+import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 import org.wikitolearn.wikirating.model.Page;
 import org.wikitolearn.wikirating.model.Revision;
 import org.wikitolearn.wikirating.repository.PageRepository;
 import org.wikitolearn.wikirating.repository.RevisionRepository;
 import org.wikitolearn.wikirating.service.mediawiki.RevisionMediaWikiService;
 
 /**
  * 
  * @author aletundo, valsdav
  *
  */
 @Service
 public class RevisionService {
 	private static final Logger LOG = LoggerFactory.getLogger(RevisionService.class);
 	@Autowired
 	private RevisionMediaWikiService revisionMediaWikiService;
 	@Autowired
 	private RevisionRepository revisionRepository;
 	@Autowired
 	private PageRepository pageRepository;
 
 	/**
 	 * This method inserts all the revisions for every page, creating the
 	 * connections between them and between the users that have written them.
 	 * 
 	 * @param lang
 	 *            String
 	 * @param apiUrl
 	 *            String The MediaWiki API url
 	 * @return CompletableFuture<Boolean>
 	 */
 	@Async
 	public CompletableFuture<Boolean> addAllRevisions(String lang, String apiUrl) {
 		Iterable<Page> pages = pageRepository.findAll();
 		pages.forEach(page -> {
 			List<Revision> revisions = revisionMediaWikiService.getAllRevisionByPageId(apiUrl, page.getPageid());
 			// Set the first and the last revisions for the current page
 			page.setFistRevision(revisions.get(0));
 			page.setLastRevision(revisions.get(revisions.size() - 1));
-			revisions.forEach(revision -> {
-				revision.setLangRevId(lang + "_" + revision.getRevid());
-				// Get the previous revision filtering the collection
-				for(Revision r : revisions){
-					if(r.getRevid() == revision.getParentid()){
-						revision.setPreviousRevision(r);
-					}
-				}
-			});
+            ListIterator<Revision> it = revisions.listIterator();
+            while(it.hasNext()){
+                Revision rev = it.next();
+                rev.setLangRevId(lang + "_" + rev.getRevid());
+                if (it.hasPrevious()){
+                    rev.setPreviousRevision(revisions.get(it.previousIndex()));
+                }
+            }
+			//saving all the revisions node
 			revisionRepository.save(revisions);
 			pageRepository.save(page);
 			LOG.info("Inserted revisions for page {}", page.getLangPageId());
 		});
 		return CompletableFuture.completedFuture(true);
 	}
 
 }