refactor: use try-with-resources for cash id db operations

src/main/java/client/inventory/manipulator/MapleCashidGenerator.java

@@ -19,16 +19,16 @@
 */
 package client.inventory.manipulator;
 
+import tools.DatabaseConnection;
+
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.HashSet;
 import java.util.Set;
-import tools.DatabaseConnection;
 
 /**
- *
  * @author RonanLana
  */
 public class MapleCashidGenerator {
@@ -37,8 +37,8 @@ public class MapleCashidGenerator {
     private static Integer runningCashid = 0;
 
     private static void loadExistentCashIdsFromQuery(Connection con, String query) throws SQLException {
-        PreparedStatement ps = con.prepareStatement(query);
+        try (PreparedStatement ps = con.prepareStatement(query);
-        ResultSet rs = ps.executeQuery();
+             ResultSet rs = ps.executeQuery()) {
 
             while (rs.next()) {
                 int id = rs.getInt(1);
@@ -46,30 +46,15 @@ public class MapleCashidGenerator {
                     existentCashids.add(id);
                 }
             }
-        
+        }
-        rs.close();
-        ps.close();
     }
 
     public static synchronized void loadExistentCashIdsFromDb() {
-        Connection con = null;
+        try (Connection con = DatabaseConnection.getConnection()) {
-        try {
-            con = DatabaseConnection.getConnection();
-            
             loadExistentCashIdsFromQuery(con, "SELECT id FROM rings");
             loadExistentCashIdsFromQuery(con, "SELECT petid FROM pets");
-            
-            con.close();
         } catch (SQLException ex) {
             ex.printStackTrace();
-        } finally {
-            try {
-                if (con != null && !con.isClosed()) {
-                    con.close();
-                }
-            } catch (SQLException e) {
-                e.printStackTrace();
-            }
         }
 
         runningCashid = 0;