java jedis (redis) cannot connect

Question

I'm trying to connect to Redis using Jedis in my java application. I'm instantiating a JedisPool object, and when I get the resource, it throws an exception saying it cannot return the resource. What is weird though is if I just instantiate a Jedis object, it connects without problems, and I can change data.

Here's my RedisDatabase class:

package me.joeleoli.proxylink.database;

import me.joeleoli.proxylink.ProxyLink;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;

public class RedisDatabase {

    private JedisPool pool;

    public RedisDatabase(String host, int port, String password) {
        ProxyLink.getInstance().getLogger().info("Attempting to establish Redis connection " + host + ":" + port);

        this.pool = new JedisPool(host, port);

        try (Jedis jedis = this.pool.getResource()) {
            if (password != null && !password.equals("")) {
                jedis.auth(password);
            }

            jedis.select(0);
            jedis.close();
        }
    }

    public JedisPool getPool() {
        return this.pool;
    }

}

Here's my error:

22:16:15 [INFO] [ProxyLink] Attempting to establish Redis connection 127.0.0.1:6379
22:16:15 [WARNING] Exception encountered when loading plugin: ProxyLink
redis.clients.jedis.exceptions.JedisException: Could not return the resource to the pool
    at redis.clients.jedis.JedisPool.returnResource(JedisPool.java:106)
    at redis.clients.jedis.JedisPool.returnResource(JedisPool.java:12)
    at redis.clients.jedis.Jedis.close(Jedis.java:3206)
    at me.joeleoli.proxylink.database.RedisDatabase.<init>(RedisDatabase.java:23)
    at me.joeleoli.proxylink.ProxyLink.onEnable(ProxyLink.java:71)
    at net.md_5.bungee.api.plugin.PluginManager.enablePlugins(PluginManager.java:227)
    at net.md_5.bungee.BungeeCord.start(BungeeCord.java:273)
    at net.md_5.bungee.BungeeCordLauncher.main(BungeeCordLauncher.java:111)
    at net.md_5.bungee.Bootstrap.main(Bootstrap.java:15)
Caused by: redis.clients.jedis.exceptions.JedisException: Could not return the resource to the pool
    at redis.clients.util.Pool.returnResourceObject(Pool.java:61)
    at redis.clients.jedis.JedisPool.returnResource(JedisPool.java:103)
    ... 8 more
Caused by: java.lang.IllegalStateException: Object has already been returned to this pool or is invalid
    at org.apache.commons.pool2.impl.GenericObjectPool.returnObject(GenericObjectPool.java:551)
    at redis.clients.util.Pool.returnResourceObject(Pool.java:59)
    ... 9 more

What does your proxylink, The exception seems like caused by your code in proxylink — GuangshengZuo, Sep 04 '17 at 02:44
@Joel Evans , you can use this alternative [redission](https://redisson.org/) for your project as an alternative — Kaviranga, Sep 04 '17 at 02:46
@GuangshengZuo at the moment, all ProxyLink does is instantiate the RedisDatabase class. So there's no way it interferes. — Joel Evans, Sep 04 '17 at 03:02
if ProxyLink does is instantiate the RedisDatabase class, how it instantiate RedisDatabase class? It will call `RedisDatabase(String host, int port, String password)` to construct, right? If so, it will execute 'ProxyLink.getInstance()' again and again. — GuangshengZuo, Sep 04 '17 at 03:18
It's a Spigot plugin. You're probably unfamiliar with Spigot. Spigot will instantiate ProxyLink and provide a few methods like onEnable, to where I can set the instance field. Then I can retrieve the instance from anywhere. Also, I can instantiate RedisDatabase in the onEnable method. It's 100% not interfering. — Joel Evans, Sep 04 '17 at 04:16

score 1 · Answer 1 · answered Sep 04 '17 at 13:54

The problem with your code is the call to jedis.close() within the try-with-resource block. The try-with-resource block with closes your resource when the block exits. Since you already closed the resource, prior to the block exiting, you end up calling close twice.

Remove the call to jedis.close within the block and just use the try-with-resource functionality.

java jedis (redis) cannot connect

1 Answers1