Keep JDBC driver diagnostics out of stderr

README.md

@@ -246,7 +246,7 @@ Rows are streamed without a CLI row limit or silent truncation. The agent's own
 
 User data lives in `~/.sqlx/`. Use `--data-dir` or `SQLX_DATA_DIR` for another location. Saved connections use AES-256-GCM with an independently generated local key. Back up the key together with the encrypted data; losing the key prevents decryption. Device identity is generated locally, and this version does not upload device information.
 
-The main executable contains no database drivers. MySQL and PostgreSQL use separate native Rust workers; Oracle and SQL Server use a separate JDBC worker. Downloaded resources are selected from the running CLI version's fixed GitHub Release manifest and verified before use. `--manifest <https-url>` selects a particular manifest or local test server.
+The main executable contains no database drivers. MySQL and PostgreSQL use separate native Rust workers; Oracle and SQL Server use a separate JDBC worker. The JDBC worker keeps vendor driver logging off, so a failed connection reports only the SQLX error; set `SQLX_JDBC_DEBUG=1` to also see the driver's own diagnostics on stderr. Downloaded resources are selected from the running CLI version's fixed GitHub Release manifest and verified before use. `--manifest <https-url>` selects a particular manifest or local test server.
 
 Downloads happen on first use and are cached afterwards. Each one prints `Downloading …`, a progress line with speed and estimated time, and a final `Downloaded … in 12.3s (390 KB/s)` line on stderr; the progress line is refreshed only when stderr is a terminal, so piped JSON stays clean. An interrupted transfer is retried up to three times, and re-running a failed command reuses every component that is already installed. To avoid waiting inside the first query or page, fetch components ahead of time:
 

java/jdbc/src/main/java/ai/ottermind/sqlx/JdbcWorker.java

@@ -9,6 +9,9 @@
 import java.nio.file.*;
 import java.sql.*;
 import java.util.*;
+import java.util.logging.Level;
+import java.util.logging.LogManager;
+import java.util.logging.Logger;
 
 public final class JdbcWorker {
     private static final ObjectMapper JSON = new ObjectMapper();
@@ -17,7 +20,18 @@ public final class JdbcWorker {
     }
     private final PrintStream out;
     JdbcWorker(PrintStream out) { this.out = out; }
+    /**
+     * Vendor drivers log connection diagnostics through java.util.logging, which floods
+     * stderr with dozens of lines when a connection fails. Keep it quiet unless
+     * SQLX_JDBC_DEBUG is set.
+     */
+    private static void quietDriverLogging() {
+        if (System.getenv("SQLX_JDBC_DEBUG") != null) return;
+        LogManager.getLogManager().reset();
+        Logger.getLogger("").setLevel(Level.OFF);
+    }
     public static void main(String[] args) {
+        quietDriverLogging();
         JdbcWorker worker = new JdbcWorker(System.out);
         try {
             worker.emit("ready", "protocol_version", 1);