Combining Spring boot and redis with docker-compose: Connection refused

I am trying to do a basic docker container(s) with spring boot and MongoDB and redis. Mongo is just fine but connection can't be established between redis and spring boot although the configuration looks ok to me.

docker-compose.yml

version: "3.9"services:  web:    build: .    ports:      - "1234:1234"    depends_on:      - redis      - db  db:    image: mongo    hostname: mongodb    ports:      - "27017:27017"  redis:    hostname: redis    image: redis    restart: always    ports:      - "6379:6379"

Dockerfile:

FROM adoptopenjdk:11ARG JAR_FILE=target/*.jarCOPY ${JAR_FILE} app.jarENTRYPOINT ["java","-jar","/app.jar"]

Config.java:

@Configuration@EnableRedisRepositoriespublic class Config{    RedisStandaloneConfiguration standaloneConfiguration() {        return new RedisStandaloneConfiguration("redis", 6379);    }    @Bean    JedisConnectionFactory jedisConnectionFactory() {        return new JedisConnectionFactory(standaloneConfiguration());    }    @Bean    public RedisTemplate<String, Object> redisTemplate() {        RedisTemplate<String, Object> template = new RedisTemplate<>();        template.setConnectionFactory(jedisConnectionFactory());        return template;    }}

Problem: All the containers are running after docker compose up. but the connection between spring and redis can't be established.

java.net.ConnectException: Connection refused (Connection refused)slot-web-1    |     at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]slot-web-1    |     at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]slot-web-1    |     at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]slot-web-1    |     at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]slot-web-1    |     at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:na]