# Connecting with Java

This guide explains how to establish a connection between a Java application and a Redis database using the <span class="s3">Jedis</span> library. It walks through the necessary setup, configuration, and execution of a simple Redis command.

## **Variables**

Certain parameters must be provided to establish a successful connection to a Redis database. Below is a breakdown of each required variable, its purpose, and where to find it. Here’s what each variable represents:

<table border="1" id="bkmrk-variable-description" style="width: 100%; border-collapse: collapse; border-color: rgb(0, 0, 0);"><thead><tr><th style="width: 11.5595%; border-color: rgb(0, 0, 0);">**Variable**

</th><th style="width: 42.4333%; border-color: rgb(0, 0, 0);">**Description**

</th><th style="width: 46.1263%; border-color: rgb(0, 0, 0);">**Purpose**

</th></tr></thead><tbody><tr><td style="width: 11.5595%; border-color: rgb(0, 0, 0);">`HOST`

</td><td style="width: 42.4333%; border-color: rgb(0, 0, 0);">Redis hostname, from the Elestio service overview page

</td><td style="width: 46.1263%; border-color: rgb(0, 0, 0);">The address of the server hosting your Redis instance.

</td></tr><tr><td style="width: 11.5595%; border-color: rgb(0, 0, 0);">`PORT`

</td><td style="width: 42.4333%; border-color: rgb(0, 0, 0);">Port for Redis connection, from the Elestio service overview page

</td><td style="width: 46.1263%; border-color: rgb(0, 0, 0);">The network port used to connect to Redis. The default port is 6379.

</td></tr><tr><td style="width: 11.5595%; border-color: rgb(0, 0, 0);">`PASSWORD`

</td><td style="width: 42.4333%; border-color: rgb(0, 0, 0);">Redis password, from the Elestio service overview page

</td><td style="width: 46.1263%; border-color: rgb(0, 0, 0);">The authentication key required to connect securely to Redis.

</td></tr></tbody></table>

These values can usually be found in the Elestio service overview details as shown in the image below, make sure to take a copy of these details and add it to the code moving ahead.

[![Screenshot 2025-05-19 at 12.23.05 PM.jpg](https://docs.elest.io/uploads/images/gallery/2025-05/scaled-1680-/screenshot-2025-05-19-at-12-23-05-pm.jpg)](https://docs.elest.io/uploads/images/gallery/2025-05/screenshot-2025-05-19-at-12-23-05-pm.jpg)

## **Prerequisites**

**Install Java**

Check if Java is installed by running:

```
java -version
```

If not installed, download it from oracle.com and install.

**Download Jedis and Dependencies**

The Jedis library enables Java applications to interact with Redis. You need to download two JAR files manually:

1. <span class="s1">**Jedis JAR**</span> (Jedis 5.1.0):
    
    [https://repo1.maven.org/maven2/redis/clients/jedis/5.1.0/jedis-5.1.0.jar](https://repo1.maven.org/maven2/redis/clients/jedis/5.1.0/jedis-5.1.0.jar)
2. **Apache Commons Pool2 JAR**<span class="s1"> (Required by Jedis):</span>
    
    [https://repo1.maven.org/maven2/org/apache/commons/commons-pool2/2.11.1/commons-pool2-2.11.1.jar](https://repo1.maven.org/maven2/org/apache/commons/commons-pool2/2.11.1/commons-pool2-2.11.1.jar)

Place both JAR files in the same directory as your Java file.

## **Code**

Once all prerequisites are set up, create a new file named <span class="s2">RedisTest.java</span> and add the following code:

```java
import redis.clients.jedis.JedisPooled;

public class RedisTest {
    public static void main(String[] args) {
        // Redis connection configuration
        String host = "HOST";
        int port = PORT; // e.g., 6379
        String password = "PASSWORD";

        // Create a Redis client
        JedisPooled jedis = new JedisPooled(host, port, password);

        try {
            // Set and get a test key
            jedis.set("testKey", "Hello Redis");
            String value = jedis.get("testKey");

            System.out.println("Connected to Redis");
            System.out.println("Retrieved value: " + value);

        } catch (Exception e) {
            System.out.println("Redis connection or operation failed: " + e.getMessage());
        }
    }
}
```

To execute the script, open the terminal or command prompt and navigate to the directory where <span class="s1">RedisTest.java</span> is located. Once in the correct directory, run the following commands:

**On Linux/macOS :**

```bash
javac -cp "jedis-5.1.0.jar:commons-pool2-2.11.1.jar" RedisTest.java
java -cp ".:jedis-5.1.0.jar:commons-pool2-2.11.1.jar" RedisTest
```

**On Windows :**

```bash
javac -cp "jedis-5.1.0.jar;commons-pool2-2.11.1.jar" RedisTest.java
java -cp ".;jedis-5.1.0.jar;commons-pool2-2.11.1.jar" RedisTest
```

If the connection is successful, the terminal will display output similar to:

```bash
Connected to Redis  
Retrieved value: Hello Redis
```