refactor: use try-with-resources for Fredrick db operations

src/main/java/client/processor/npc/FredrickProcessor.java

@@ -29,15 +29,7 @@ import client.inventory.Item;
 import client.inventory.ItemFactory;
 import client.inventory.MapleInventory;
 import client.inventory.MapleInventoryType;
-import java.sql.Connection;
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.sql.Timestamp;
-import java.util.LinkedList;
-import java.util.List;
 import client.inventory.manipulator.MapleInventoryManipulator;
-import java.util.Collections;
 import net.server.Server;
 import net.server.world.World;
 import server.MapleItemInformationProvider;
@@ -47,6 +39,11 @@ import tools.FilePrinter;
 import tools.MaplePacketCreator;
 import tools.Pair;
 
+import java.sql.*;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
 /**
  *
  * @author RonanLana - synchronization of Fredrick modules and operation results
@@ -100,10 +97,8 @@ public class FredrickProcessor {
     }
     
     public static void removeFredrickLog(int cid) {
-        try {
+        try (Connection con = DatabaseConnection.getConnection()) {
-            Connection con = DatabaseConnection.getConnection();
             removeFredrickLog(con, cid);
-            con.close();
         } catch (SQLException sqle) {
             sqle.printStackTrace();
         }
@@ -112,22 +107,19 @@ public class FredrickProcessor {
     private static void removeFredrickLog(Connection con, int cid) throws SQLException {
         try (PreparedStatement ps = con.prepareStatement("DELETE FROM `fredstorage` WHERE `cid` = ?")) {
             ps.setInt(1, cid);
-            ps.execute();
+            ps.executeUpdate();
         }
     }
     
     public static void insertFredrickLog(int cid) {
-        try {
+        try (Connection con = DatabaseConnection.getConnection()) {
-            Connection con = DatabaseConnection.getConnection();
 
             removeFredrickLog(con, cid);
             try (PreparedStatement ps = con.prepareStatement("INSERT INTO `fredstorage` (`cid`, `daynotes`, `timestamp`) VALUES (?, 0, ?)")) {
                 ps.setInt(1, cid);
                 ps.setTimestamp(2, new Timestamp(System.currentTimeMillis()));
-                ps.execute();
+                ps.executeUpdate();
             }
-            
-            con.close();
         } catch (SQLException sqle) {
             sqle.printStackTrace();
         }
@@ -146,30 +138,25 @@ public class FredrickProcessor {
             }
         }
 
-        try {
+        try (Connection con = DatabaseConnection.getConnection();
-            Connection con = DatabaseConnection.getConnection();
+             PreparedStatement ps = con.prepareStatement("DELETE FROM `notes` WHERE `from` LIKE ? AND `to` LIKE ?")) {
-            try (PreparedStatement ps = con.prepareStatement("DELETE FROM `notes` WHERE `from` LIKE ? AND `to` LIKE ?")) {
             ps.setString(1, "FREDRICK");
 
             for (String cname : expiredCnames) {
                 ps.setString(2, cname);
                 ps.executeBatch();
             }
-            }
-            con.close();
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
     
     public static void runFredrickSchedule() {
-        try {
+        try (Connection con = DatabaseConnection.getConnection()) {
-            Connection con = DatabaseConnection.getConnection();
-            
             List<Pair<Integer, Integer>> expiredCids = new LinkedList<>();
             List<Pair<Pair<Integer, String>, Integer>> notifCids = new LinkedList<>();
-            try (PreparedStatement ps = con.prepareStatement("SELECT * FROM fredstorage f LEFT JOIN (SELECT id, name, world, lastLogoutTime FROM characters) AS c ON c.id = f.cid")) {
+            try (PreparedStatement ps = con.prepareStatement("SELECT * FROM fredstorage f LEFT JOIN (SELECT id, name, world, lastLogoutTime FROM characters) AS c ON c.id = f.cid");
-                try (ResultSet rs = ps.executeQuery()) {
+                 ResultSet rs = ps.executeQuery()) {
                 long curTime = System.currentTimeMillis();
 
                 while (rs.next()) {
@@ -200,7 +187,7 @@ public class FredrickProcessor {
                         }
                     }
                 }
-                }
+
             }
 
             if (!expiredCids.isEmpty()) {
@@ -258,22 +245,18 @@ public class FredrickProcessor {
                     ps.executeBatch();
                 }
             }
-            
-            con.close();
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 
     private static boolean deleteFredrickItems(int cid) {
-        try {
+        try (Connection con = DatabaseConnection.getConnection();
-            Connection con = DatabaseConnection.getConnection();
+             PreparedStatement ps = con.prepareStatement("DELETE FROM `inventoryitems` WHERE `type` = ? AND `characterid` = ?")) {
-            try (PreparedStatement ps = con.prepareStatement("DELETE FROM `inventoryitems` WHERE `type` = ? AND `characterid` = ?")) {
             ps.setInt(1, ItemFactory.MERCHANT.getValue());
             ps.setInt(2, cid);
-                ps.execute();
+            ps.executeUpdate();
-            }
+
-            con.close();
             return true;
         } catch (SQLException e) {
             e.printStackTrace();