redis/jedis · error · JedisConnectionException

It seems like server has closed the connection.

Error message

It seems like server has closed the connection.

What it means

RedisInputStream.readLine builds a reply line byte by byte; if the very first byte available is an immediate end-of-stream producing an empty line, the server has closed the connection without sending any reply. Jedis throws JedisConnectionException because no response exists to parse.

Solutions

1. Discard and reopen the connection; retry the command on a fresh connection (idempotent commands only).
2. Enable Jedis pool testOnBorrow/testWhileIdle and set pool eviction settings so dead connections are pruned.
3. Match client socket timeout below the server's `timeout` setting and any LB idle timeout; send periodic PINGs or enable TCP keepalive.
4. Check Redis server logs (and `CLIENT LIST`) for kills or restarts around the failure time.

Example fix

// before
JedisPool pool = new JedisPool(config, host);
// idle connections die silently
// after
JedisPool pool = new JedisPoolBuilder()
  .connectionConfig(JedisClientConfig.builder()
      .timeoutMillis(30000)
      .blockingSocketTimeoutMillis(0).build())
  .poolConfig(new GenericObjectPoolConfig.Builder()
      .testWhileIdle(true)
      .timeBetweenEvictionRunsMillis(30000).build())
  .hostAndPort(host, port).build();

// before executing: ensure pool validates connections
if (!jedis.isConnected()) { jedis = pool.getResource(); }

try {
  return jedis.get(key);
} catch (JedisConnectionException e) {
  // server closed connection; retry once on a fresh resource
  try (Jedis fresh = pool.getResource()) {
    return fresh.get(key);
  }
}

When it happens

Trigger: Thrown from the public readLine (used by message, readErrorLineIfPossible, readDoubleCrLf, readBigIntegerCrLf) when the accumulated line is empty because the underlying stream hit EOF immediately (ensureFill saw limit == -1).

Common situations: Redis server restarted or crashed between request and reply; server-side client timeout (timeout config) killing idle connections; a load balancer idling out the TCP connection; network partition dropping the socket.

Related errors

• Unexpected end of stream.
• Failed to create socket.
• It seems like server has closed the connection.
• All configured databases are unhealthy. Cannot initialize…
• Attempting to write to a broken connection.

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/21085ee413fe0779. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/util/RedisInputStream.java:96

      byte b = buf[count++];
      if (b == '\r') {
        ensureFill(); // Must be one more byte

        byte c = buf[count++];
        if (c == '\n') {
          break;
        }
        sb.append((char) b);
        sb.append((char) c);
      } else {
        sb.append((char) b);
      }
    }

    final String reply = sb.toString();
    if (reply.isEmpty()) {
      throw new JedisConnectionException("It seems like server has closed the connection.");
    }

    return reply;
  }

  public byte[] readLineBytes() {

    /*
     * This operation should only require one fill. In that typical case we optimize allocation and
     * copy of the byte array. In the edge case where more than one fill is required then we take a
     * slower path and expand a byte array output stream as is necessary.
     */

    ensureFill();

    int pos = count;
    final byte[] buf = this.buf;
    while (true) {

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