From fe5076a8267b52e05f75773c2d9719064c8b45fc Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Thu, 19 Feb 2026 06:05:07 +0000
Subject: [PATCH] Refactor DatabaseHandler to use local Statement objects

Refactored `DatabaseHandler.java` to remove the static shared `Statement` field, which was causing concurrency issues and potential resource leaks.
- `execQuery`: Now uses a local `Statement` and calls `closeOnCompletion()` to ensure the statement is closed when the returned `ResultSet` is closed.
- `execAction`: Now uses a local `Statement` within a try-with-resources block for automatic resource management.
- Improved error handling in `execQuery` to close the statement if an exception occurs during execution.

This change improves thread safety and resource management in database operations.

Co-authored-by: G30RG3-GJ <203693057+G30RG3-GJ@users.noreply.github.com>
---
 .../assistant/database/DatabaseHandler.java   | 20 +++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/library/assistant/database/DatabaseHandler.java b/src/library/assistant/database/DatabaseHandler.java
index e9c4f53..a6127cc 100644
--- a/src/library/assistant/database/DatabaseHandler.java
+++ b/src/library/assistant/database/DatabaseHandler.java
@@ -35,7 +35,6 @@ public final class DatabaseHandler {
 
     private static final String DB_URL = "jdbc:derby:database;create=true";
     private static Connection conn = null;
-    private static Statement stmt = null;
 
     static {
         createConnection();
@@ -109,23 +108,28 @@ private static void readDBTable(Set<String> set, DatabaseMetaData dbmeta, String
     }
 
     public ResultSet execQuery(String query) {
-        ResultSet result;
+        Statement stmt = null;
         try {
             stmt = conn.createStatement();
-            result = stmt.executeQuery(query);
+            stmt.closeOnCompletion();
+            return stmt.executeQuery(query);
         }
         catch (SQLException ex) {
             System.out.println("Exception at execQuery:dataHandler" + ex.getLocalizedMessage());
+            if (stmt != null) {
+                try {
+                    stmt.close();
+                }
+                catch (SQLException e) {
+                    LOGGER.log(Level.ERROR, "{}", e);
+                }
+            }
             return null;
         }
-        finally {
-        }
-        return result;
     }
 
     public boolean execAction(String qu) {
-        try {
-            stmt = conn.createStatement();
+        try (Statement stmt = conn.createStatement()) {
             stmt.execute(qu);
             return true;
         }