added a little doc

src/main/java/com/commafeed/backend/DatabaseCleaner.java

@@ -19,6 +19,10 @@ import com.commafeed.backend.model.Feed;
 import com.commafeed.backend.model.FeedSubscription;
 import com.commafeed.backend.services.ApplicationSettingsService;
 
+/**
+ * Contains utility methods for cleaning the database
+ * 
+ */
 public class DatabaseCleaner {
 
 	private static Logger log = LoggerFactory.getLogger(DatabaseCleaner.class);

src/main/java/com/commafeed/backend/DatabaseUpdater.java

@@ -20,6 +20,10 @@ import liquibase.structure.DatabaseObject;
 
 import com.commafeed.backend.services.ApplicationPropertiesService;
 
+/**
+ * Executes needed liquibase database schema upgrades
+ * 
+ */
 @Stateless
 @TransactionManagement(TransactionManagementType.BEAN)
 public class DatabaseUpdater {

src/main/java/com/commafeed/backend/FixedSizeSortedSet.java

@@ -5,6 +5,11 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 
+/**
+ * List wrapper that sorts its elements in the order provided by given comparator and ensure a maximum capacity.
+ * 
+ * 
+ */
 public class FixedSizeSortedSet<E> {
 
 	private List<E> inner;

src/main/java/com/commafeed/backend/HttpGetter.java

@@ -41,6 +41,10 @@ import org.apache.http.util.EntityUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/**
+ * Smart HTTP getter
+ * 
+ */
 public class HttpGetter {
 
 	private static Logger log = LoggerFactory.getLogger(HttpGetter.class);

src/main/java/com/commafeed/backend/ScheduledTasks.java

@@ -13,6 +13,10 @@ import org.slf4j.LoggerFactory;
 
 import com.commafeed.backend.services.ApplicationSettingsService;
 
+/**
+ * Contains all scheduled tasks
+ * 
+ */
 @Stateless
 public class ScheduledTasks {
 	protected final static Logger log = LoggerFactory.getLogger(ScheduledTasks.class);
@@ -26,7 +30,9 @@ public class ScheduledTasks {
 	@PersistenceContext
 	EntityManager em;
 
-	// every day at midnight
+	/**
+	 * clean old read statuses, runs every day at midnight
+	 */
 	@Schedule(hour = "0", persistent = false)
 	private void cleanupOldStatuses() {
 		Date threshold = applicationSettingsService.get().getUnreadThreshold();

src/main/java/com/commafeed/backend/StartupBean.java

@@ -25,6 +25,10 @@ import com.commafeed.backend.services.ApplicationSettingsService;
 import com.commafeed.backend.services.UserService;
 import com.google.api.client.util.Maps;
 
+/**
+ * Starting point of the application
+ * 
+ */
 @Startup
 @Singleton
 @ConcurrencyManagement(ConcurrencyManagementType.BEAN)
@@ -56,14 +60,19 @@ public class StartupBean {
 	private void init() {
 
 		startupTime = System.currentTimeMillis();
+
+		// update database schema
 		databaseUpdater.update();
 
 		if (applicationSettingsDAO.getCount() == 0) {
+			// import initial data
 			initialData();
 		}
 		applicationSettingsService.applyLogLevel();
 
 		initSupportedLanguages();
+
+		// start fetching feeds
 		taskGiver.start();
 	}
 
@@ -83,6 +92,9 @@ public class StartupBean {
 		}
 	}
 
+	/**
+	 * create default users
+	 */
 	private void initialData() {
 		log.info("Populating database with default values");
 

src/main/java/com/commafeed/backend/feeds/FaviconFetcher.java

@@ -81,7 +81,7 @@ public class FaviconFetcher {
 		return bytes;
 	}
 
-	boolean isValidIconResponse(byte[] content, String contentType) {
+	private boolean isValidIconResponse(byte[] content, String contentType) {
 		if (content == null) {
 			return false;
 		}

src/main/java/com/commafeed/backend/feeds/FeedRefreshExecutor.java

@@ -10,6 +10,11 @@ import java.util.concurrent.atomic.AtomicInteger;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/**
+ * Wraps a {@link ThreadPoolExecutor} instance. Blocks when queue is full instead of rejecting the task. Allow priority queueing by using
+ * {@link Task} instead of {@link Runnable}
+ * 
+ */
 public class FeedRefreshExecutor {
 
 	private static Logger log = LoggerFactory.getLogger(FeedRefreshExecutor.class);

src/main/java/com/commafeed/backend/feeds/FeedRefreshTaskGiver.java

@@ -25,6 +25,11 @@ import com.google.api.client.util.Maps;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Queues;
 
+/**
+ * Infinite loop fetching feeds from the database and queuing them to the {@link FeedRefreshWorker} pool. Also handles feed database updates
+ * at the end of the cycle through {@link #giveBack(Feed)}.
+ * 
+ */
 @ApplicationScoped
 public class FeedRefreshTaskGiver {
 

src/main/java/com/commafeed/backend/feeds/FeedRefreshWorker.java

@@ -22,6 +22,10 @@ import com.commafeed.backend.model.FeedEntry;
 import com.commafeed.backend.services.ApplicationSettingsService;
 import com.sun.syndication.io.FeedException;
 
+/**
+ * Calls {@link FeedFetcher} and handles its outcome
+ * 
+ */
 @ApplicationScoped
 public class FeedRefreshWorker {
 

src/main/java/com/commafeed/backend/feeds/FeedUtils.java

@@ -36,6 +36,10 @@ import com.steadystate.css.parser.CSSOMParser;
 
 import edu.uci.ics.crawler4j.url.URLCanonicalizer;
 
+/**
+ * Utility methods related to feed handling
+ * 
+ */
 public class FeedUtils {
 
 	protected static Logger log = LoggerFactory.getLogger(FeedUtils.class);

src/main/java/com/commafeed/backend/model/AbstractModel.java

@@ -8,6 +8,10 @@ import javax.persistence.Id;
 import javax.persistence.MappedSuperclass;
 import javax.persistence.TableGenerator;
 
+/**
+ * Abstract model for all entities, defining id and table generator
+ * 
+ */
 @SuppressWarnings("serial")
 @MappedSuperclass
 public abstract class AbstractModel implements Serializable {

src/main/java/com/commafeed/backend/pubsubhubbub/SubscriptionHandler.java

@@ -22,8 +22,13 @@ import com.commafeed.backend.feeds.FeedRefreshTaskGiver;
 import com.commafeed.backend.feeds.FeedUtils;
 import com.commafeed.backend.model.Feed;
 import com.commafeed.backend.services.ApplicationSettingsService;
+import com.commafeed.frontend.rest.resources.PubSubHubbubCallbackREST;
 import com.google.common.collect.Lists;
 
+/**
+ * Sends push subscription requests. Callback is handled by {@link PubSubHubbubCallbackREST}
+ * 
+ */
 public class SubscriptionHandler {
 
 	private static Logger log = LoggerFactory.getLogger(SubscriptionHandler.class);

src/main/java/com/commafeed/backend/rome/OPML11Generator.java

@@ -4,6 +4,10 @@ import org.jdom.Element;
 
 import com.sun.syndication.feed.opml.Opml;
 
+/**
+ * Add missing title to the generated OPML
+ * 
+ */
 public class OPML11Generator extends com.sun.syndication.io.impl.OPML10Generator {
 
 	public OPML11Generator() {

src/main/java/com/commafeed/backend/rome/OPML11Parser.java

@@ -5,6 +5,10 @@ import org.jdom.Element;
 
 import com.sun.syndication.io.impl.OPML10Parser;
 
+/**
+ * Support for OPML 1.1 parsing
+ * 
+ */
 public class OPML11Parser extends OPML10Parser {
 
 	public OPML11Parser() {

src/main/java/com/commafeed/backend/rome/RSS090DescriptionConverter.java

@@ -6,6 +6,10 @@ import com.sun.syndication.feed.synd.SyndContentImpl;
 import com.sun.syndication.feed.synd.SyndEntry;
 import com.sun.syndication.feed.synd.impl.ConverterForRSS090;
 
+/**
+ * Support description tag for RSS09
+ *
+ */
 public class RSS090DescriptionConverter extends ConverterForRSS090 {
 
 	@Override

src/main/java/com/commafeed/backend/rome/RSS090DescriptionParser.java

@@ -6,6 +6,10 @@ import com.sun.syndication.feed.rss.Description;
 import com.sun.syndication.feed.rss.Item;
 import com.sun.syndication.io.impl.RSS090Parser;
 
+/**
+ * Support description tag for RSS09
+ *
+ */
 public class RSS090DescriptionParser extends RSS090Parser {
 
 	@Override

src/main/java/com/commafeed/backend/services/MailService.java

@@ -18,6 +18,10 @@ import org.slf4j.LoggerFactory;
 import com.commafeed.backend.model.ApplicationSettings;
 import com.commafeed.backend.model.User;
 
+/**
+ * Mailing service
+ * 
+ */
 @SuppressWarnings("serial")
 public class MailService implements Serializable {
 

src/main/java/com/commafeed/backend/services/PasswordEncryptionService.java

@@ -15,7 +15,7 @@ import org.slf4j.LoggerFactory;
 
 import com.commafeed.backend.dao.UserDAO;
 
-// http://www.javacodegeeks.com/2012/05/secure-password-storage-donts-dos-and.html
+// taken from http://www.javacodegeeks.com/2012/05/secure-password-storage-donts-dos-and.html
 @SuppressWarnings("serial")
 public class PasswordEncryptionService implements Serializable {