Error while validating pooled Connection object.

Error message

Error while validating pooled Connection object.

What it means

This warning is logged by ConnectionFactory.validateObject when a pooled connection fails its periodic health check. The pool calls validateObject before handing a connection to the caller; any exception during re-authentication or PING (socket closed, timeout, protocol error) is swallowed and the connection is reported invalid so the pool destroys it. It is diagnostic, not fatal — the pool simply evicts the bad connection.

Solutions

Check Redis server logs and network stability between client and server; the underlying exception printed with this warning names the root cause.
Enable pool test-while-idle / eviction settings so dead connections are culled before validation-time failures.
If re-authentication failures, confirm username/password in JedisClientConfig match current Redis ACLs.
Upgrade or tune socket timeout / connect timeout so transient latency does not fail PING.
If MOVING/retired events are involved, ensure maintenance-event handling is enabled so retired connections are replaced cleanly.

Example fix

// before
JedisPool pool = new JedisPool(config, host); // defaults: no idle testing
// after
GenericObjectPoolConfig<Jedis> pc = new GenericObjectPoolConfig<>();
pc.setTestWhileIdle(true);
pc.setTimeBetweenEvictionRunsMillis(30000);
pc.setMinEvictableIdleTimeMillis(60000);
JedisPool pool = new JedisPool(pc, config, host, port);

Defensive patterns

Strategy: retry

Validate before calling

try (Jedis probe = new Jedis(host, port)) {
  probe.ping(); // throws quickly if Redis unreachable before pool use
}

Try / catch

try { jedis.ping(); } catch (JedisConnectionException e) { logger.warn("connection dead, will be evicted", e); pool.clear(); }

Prevention

Enable testWhileIdle with a timeBetweenEvictionRunsMillis below any firewall idle timeout
Keep soTimeout above the slowest command's worst-case latency
Rotate client credentials in sync with Redis ACL changes
Monitor Redis restarts/failovers so validation warnings correlate with known events

When it happens

Trigger: PING to Redis times out or throws (server restarted, network drop, connection already closed); reAuthenticate() fails because the password/username changed or ACLs were updated; the connection was marked retired by a MOVING maintenance push after the ping.

Common situations: Redis server restart or failover while a pool holds idle connections; firewall/NAT silently dropping idle TCP connections (validate then fails on first use after idle); credentials rotated in Redis ACL without updating the client config.

Related errors

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/a3b1e27439b23963. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/ConnectionFactory.java:238

  }

  @Override
  public boolean validateObject(PooledObject<Connection> pooledConnection) {
    final Connection jedis = pooledConnection.getObject();
    try {
      // check HostAndPort ??
      if (!jedis.isConnected()) {
        return false;
      }
      if (jedis.isRetired()) {
        return false; // marked by a maintenance marking pass -> recycle
      }
      reAuthenticate(jedis);
      // Re-check after the ping: its read may consume a buffered MOVING push whose inline
      // marking pass marks this connection.
      return jedis.ping() && !jedis.isRetired();
    } catch (final Exception e) {
      logger.warn("Error while validating pooled Connection object.", e);
      return false;
    }
  }

  private void reAuthenticate(Connection jedis) throws Exception {
    try {
      String result = jedis.reAuthenticate();
      if (result != null && !result.equals("OK")) {
        String msg = "Re-authentication failed with server response: " + result;
        Exception failedAuth = new JedisAuthenticationException(msg);
        logger.error(failedAuth.getMessage(), failedAuth);
        authXEventListener.onConnectionAuthenticationError(failedAuth);
        return;
      }
    } catch (Exception e) {
      logger.error("Error while re-authenticating connection", e);
      authXEventListener.onConnectionAuthenticationError(e);
      throw e;

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