Fix minor Checkstyle violations

- Mostly missing JavaDoc, some line lengths

src/main/java/fr/xephi/authme/command/executable/authme/debug/MySqlDefaultChanger.java

@@ -172,6 +172,11 @@ class MySqlDefaultChanger implements DebugSection {
             + sender.getName() + "'");
     }
 
+    /**
+     * Outputs the current definitions of all {@link Columns} which can be migrated.
+     *
+     * @param sender command sender to output the data to
+     */
     private void showColumnDetails(CommandSender sender) {
         sender.sendMessage(ChatColor.BLUE + "MySQL column details");
         final String tableName = settings.getProperty(DatabaseSettings.MYSQL_TABLE);

src/main/java/fr/xephi/authme/datasource/MySQL.java

@@ -28,6 +28,10 @@ import java.util.Set;
 import static fr.xephi.authme.datasource.SqlDataSourceUtils.getNullableLong;
 import static fr.xephi.authme.datasource.SqlDataSourceUtils.logSqlException;
 
+/**
+ * MySQL data source.
+ */
+@SuppressWarnings({"checkstyle:AbbreviationAsWordInName"}) // Justification: Class name cannot be changed anymore
 public class MySQL implements DataSource {
 
     private boolean useSsl;
@@ -728,6 +732,13 @@ public class MySQL implements DataSource {
         return players;
     }
 
+    /**
+     * Creates a {@link PlayerAuth} object with the data from the provided result set.
+     *
+     * @param row the result set to read from
+     * @return generated player auth object with the data from the result set
+     * @throws SQLException .
+     */
     private PlayerAuth buildAuthFromResultSet(ResultSet row) throws SQLException {
         String salt = col.SALT.isEmpty() ? null : row.getString(col.SALT);
         int group = col.GROUP.isEmpty() ? -1 : row.getInt(col.GROUP);

src/main/java/fr/xephi/authme/datasource/SQLite.java

@@ -28,6 +28,7 @@ import static fr.xephi.authme.datasource.SqlDataSourceUtils.logSqlException;
 /**
  * SQLite data source.
  */
+@SuppressWarnings({"checkstyle:AbbreviationAsWordInName"}) // Justification: Class name cannot be changed anymore
 public class SQLite implements DataSource {
 
     private final Settings settings;

src/main/java/fr/xephi/authme/listener/PlayerListener19Spigot.java

@@ -12,10 +12,11 @@ import javax.inject.Inject;
 
 public class PlayerListener19Spigot implements Listener {
 
+    private static boolean isPlayerSpawnLocationEventCalled = false;
+
     @Inject
     private TeleportationService teleportationService;
 
-    private static boolean isPlayerSpawnLocationEventCalled = false;
 
     public static boolean isPlayerSpawnLocationEventCalled() {
         return isPlayerSpawnLocationEventCalled;

src/main/java/fr/xephi/authme/permission/handlers/LuckPermsHandler.java

@@ -62,7 +62,8 @@ public class LuckPermsHandler implements PermissionHandler {
             return false;
         }
 
-        DataMutateResult result = user.setPermissionUnchecked(luckPermsApi.getNodeFactory().makeGroupNode(newGroup).build());
+        DataMutateResult result = user.setPermissionUnchecked(
+            luckPermsApi.getNodeFactory().makeGroupNode(newGroup).build());
         if (result == DataMutateResult.FAIL) {
             return false;
         }

src/main/java/fr/xephi/authme/process/register/ProcessSyncEmailRegister.java

@@ -10,7 +10,9 @@ import org.bukkit.entity.Player;
 
 import javax.inject.Inject;
 
-
+/**
+ * Performs synchronous tasks after a successful {@link RegistrationType#EMAIL email registration}.
+ */
 public class ProcessSyncEmailRegister implements SynchronousProcess {
 
     @Inject
@@ -22,6 +24,11 @@ public class ProcessSyncEmailRegister implements SynchronousProcess {
     ProcessSyncEmailRegister() {
     }
 
+    /**
+     * Performs sync tasks for a player which has just registered by email.
+     *
+     * @param player the recently registered player
+     */
     public void processEmailRegister(Player player) {
         service.send(player, MessageKey.ACCOUNT_NOT_ACTIVATED);
         limboService.replaceTasksAfterRegistration(player);

src/main/java/fr/xephi/authme/process/register/ProcessSyncPasswordRegister.java

@@ -15,6 +15,7 @@ import org.bukkit.entity.Player;
 import javax.inject.Inject;
 
 /**
+ * Performs synchronous tasks after a successful {@link RegistrationType#PASSWORD password registration}.
  */
 public class ProcessSyncPasswordRegister implements SynchronousProcess {
 
@@ -46,6 +47,11 @@ public class ProcessSyncPasswordRegister implements SynchronousProcess {
         }
     }
 
+    /**
+     * Processes a player having registered with a password.
+     *
+     * @param player the newly registered player
+     */
     public void processPasswordRegister(Player player) {
         service.send(player, MessageKey.REGISTER_SUCCESS);
 

src/main/java/fr/xephi/authme/settings/SettingsWarner.java

@@ -56,9 +56,9 @@ public class SettingsWarner {
         // Warn if spigot.yml has settings.bungeecord set to true but config.yml has Hooks.bungeecord set to false
         if (Utils.isSpigot() && Bukkit.spigot().getConfig().getBoolean("settings.bungeecord")
             && !settings.getProperty(HooksSettings.BUNGEECORD)) {
-            ConsoleLogger.warning("Note: Hooks.bungeecord is set to false but your server appears to be running in" +
-                " bungeecord mode (see your spigot.yml). In order to allow the datasource caching and the AuthMeBungee" +
-                " add-on to work properly you have to enable this option!");
+            ConsoleLogger.warning("Note: Hooks.bungeecord is set to false but your server appears to be running in"
+                + " bungeecord mode (see your spigot.yml). In order to allow the datasource caching and the"
+                + " AuthMeBungee add-on to work properly you have to enable this option!");
         }
 
         // Check if argon2 library is present and can be loaded

src/main/java/fr/xephi/authme/task/purge/PurgeExecutor.java

@@ -61,6 +61,11 @@ public class PurgeExecutor {
         purgePermissions(players);
     }
 
+    /**
+     * Purges data from the AntiXray plugin.
+     *
+     * @param cleared the players whose data should be cleared
+     */
     synchronized void purgeAntiXray(Collection<String> cleared) {
         if (!settings.getProperty(PurgeSettings.REMOVE_ANTI_XRAY_FILE)) {
             return;
@@ -95,6 +100,11 @@ public class PurgeExecutor {
         ConsoleLogger.info(ChatColor.GOLD + "Deleted " + names.size() + " user accounts");
     }
 
+    /**
+     * Purges data from the LimitedCreative plugin.
+     *
+     * @param cleared the players whose data should be cleared
+     */
     synchronized void purgeLimitedCreative(Collection<String> cleared) {
         if (!settings.getProperty(PurgeSettings.REMOVE_LIMITED_CREATIVE_INVENTORIES)) {
             return;
@@ -191,6 +201,11 @@ public class PurgeExecutor {
         ConsoleLogger.info("AutoPurge: Removed " + deletedFiles + " EssentialsFiles");
     }
 
+    /**
+     * Removes permission data (groups a user belongs to) for the given players.
+     *
+     * @param cleared the players to remove data for
+     */
     synchronized void purgePermissions(Collection<OfflinePlayer> cleared) {
         if (!settings.getProperty(PurgeSettings.REMOVE_PERMISSIONS)) {
             return;