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Can't connect Java and MySQL on docker

When I run the docker compose, it returns the error
Caused by: java.net.ConnectException: Connection refused (Connection
refused)
I don't have much experience with docker.. what am i doing wrong?
My docker compose:
version: '3.5'
services:
mysql-service:
image: mysql:5.7
networks:
- phonebook-network
environment:
- MYSQL_ROOT_PASSWORD=admin
- MYSQL_USER=admin
- MYSQL_PASSWORD=admin
- MYSQL_DATABASE=PhoneBook
restart: on-failure
phonebook-service:
build:
context: ./
args:
JAR_FILE: ./Phonebook-0.0.1-SNAPSHOT.jar
ports:
- "8080:8080"
environment:
- DB_HOST=jdbc:mysql://mysql-service:3306/PhoneBook?useTimezone=true&serverTimezone=UTC&useSSL=false
- DB_USERNAME:admin
- DB_PASSWORD:admin
networks:
- phonebook-network
depends_on:
- mysql-service
restart: on-failure
networks:
phonebook-network:
driver: bridge
My dockerfile:
FROM openjdk:11-jdk-slim
VOLUME /phoneBook
ARG JAR_FILE
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

First, ensure the ports are exposed in MySQL as well:
services:
mysql-service:
image: mysql:5.7
networks:
- phonebook-network
ports:
- "3306:3306"
environment:
- MYSQL_ROOT_PASSWORD=admin
- MYSQL_USER=admin
- MYSQL_PASSWORD=admin
- MYSQL_DATABASE=PhoneBook
restart: on-failure
the "depends_on" config dont resolve the problem about the order that the containers start?
Yes, the depends_on ensures that the MySQL container will start before the Java one, but it might happen that MySQL itself takes a long time to bootstrap, so the container is ready but the process inside is not.
If the problem still persists, this can be a possible solution: create a docker_entrypoint.sh file at the root of your project. This also assumes the container has netcat installed.
#!/usr/bin/env bash
echo "Waiting for MySQL..."
# I'm assuming you're running it in a default port (3306)
until nc -vz "mysql-service" 3306; do
>&2 echo "Waiting for MySQL to be available..."
sleep 0.1
done
echo "MySQL started"
java -jar /app.jar
then modify your Dockerfile:
FROM openjdk:11-jdk-slim
VOLUME /phoneBook
ARG JAR_FILE
RUN apt-get update --fix-missing \
&& apt-get install -y --no-install-recommends netcat \
&& rm -rf /var/lib/apt/lists/*
COPY ${JAR_FILE} app.jar
COPY ./docker_entrypoint.sh docker_entrypoint.sh
RUN chmod 100 docker_entrypoint.sh
ENTRYPOINT [ "./docker_entrypoint.sh" ]
I don't have a way to test this right now, but let me know if this works.

Docker compose connection between java and mysql container not possible

I have an java spring / hibernate application and I cant create a connection beween the mysql and java containers. When I start just the mysql Container and run the java application manualy in CMD it works fine. But once the java application runs in a container I get the following problem:
bookAPI | com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
bookAPI |
bookAPI | The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
bookAPI | at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.21.jar!/:8.0.21]
bookAPI | at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) ~[mysql-connector-java-8.0.21.jar!/:8.0.21]
If I understand the error correctly the java container can send to the mysql container but not the other way around. I have linked the java container to the mysql container. Anyone knows how to connect these containers correctly?
My docker-compose.yml looks like this:
version: '3'
services:
db:
image: mysql:5.7
container_name: mysql
environment:
MYSQL_ROOT_PASSWORD: aaaaaa
MYSQL_DATABASE: bookAPI
MYSQL_USER: aaaaaa
MYSQL_PASSWORD: aaaaaa
ports:
- 3306:3306
phpmyadmin:
image: phpmyadmin/phpmyadmin
container_name: phpmyadmin
links:
- db
environment:
PMA_HOST: db
PMA_PORT: 3306
PMA_ARBITRARY: 1
restart: always
ports:
- 8081:80
java:
container_name: bookAPI
image: openjdk:8
depends_on:
- db
volumes:
- ./:/app
working_dir: /app
command: bash -c "cd /app && java -jar bookAPI.jar"
stdin_open: true
tty: true
ports:
- 8080:8080
links:
- db

You can also directly override the applications.properties with docker-compose environment variables like this :
java:
container_name: bookAPI
image: openjdk:8
volumes:
- ./:/app
working_dir: /app
command: bash -c "cd /app && java -jar bookAPI.jar"
stdin_open: true
tty: true
environment:
spring.datasource.url="jdbc:mysql://db:3306/bookAPI""
links:
- db
ports:
- 8080:8080
I would recomment you tu use depends_on db instead of links
depends_on:
- db

Okay, I solved the problem. To connect the spring application with another docker container you need to change the application.properties url value from localhost or ip to the docker maysql container name. Thats tricky while running it localy or run maven install so the best pracice is to overwrite it while starting the application in container.
java:
container_name: bookAPI
image: openjdk:8
volumes:
- ./:/app
working_dir: /app
command: bash -c "cd /app && java -jar bookAPI.jar --spring.datasource.url="jdbc:mysql://db:3306/bookAPI""
stdin_open: true
tty: true
links:
- db
ports:
- 8080:8080

Jar not being found when running tomcat war in Docker

I've made a war to run on my tomcat server in a Docker container. The servlet runs fine in eclipse, but when I have compiled it put it in my Docker it isn't loading in the required classes properly.
Project structure and manifest file
When I try and access the servlet using my browser I get this error.
Error in browser
I went into the Docker container and checked that gurobi.jar is still in WEB-INF/lib/ and it is.
I don't know why this wouldn't be able to find the jar, as it works fine when it's in Eclipse.
docker-compose.yml
version: '3'
services:
db:
image: mysql:5.7
ports:
- '3306:3306'
environment:
MYSQL_DATABASE: 'projectdb'
MYSQL_USER: ''
MYSQL_PASSWORD: ''
MYSQL_ROOT_PASSWORD: ''
web:
build:
context: .
dockerfile: Dockerfile
command: python manage.py runserver 0.0.0.0:8000
volumes:
- .:/code
- /var/run/docker.sock:/var/run/docker.sock
ports:
- "8000:8000"
depends_on:
- db
tomcat:
image: tomcat
ports:
- "8080:8080"
volumes:
- ./GurServ.war:/usr/local/tomcat/webapps/GurServ.war
java:
image: bitnami/java:latest
volumes:
- .:/app
- .:/code
Dockerfile
FROM python:3
ENV PYTHONUNBUFFERED 1
RUN mkdir /code
WORKDIR /code
COPY requirements.txt /code/
RUN pip install -r requirements.txt
COPY . /code/
EXPOSE 8000
CMD exec gunicorn djangoapp.wsgi:application - bind 0.0.0.0:8000 - workers 3
Project structure
...
Java Resources
src
...
WebContent
META-INF
MANIFEST.MF
WEB-INF
gurobi-javadoc.jar
gurobi.jar

Docker&Java: building doesn't reflect the new files

I've just started to use Docker and I don't know why the Wildfly's docker container doesn't have the latest files even though it copies the war. I have a JS file which I've changed things in it, but whenever I access 127.0.0.1:8080/static/js/myjs.js I still get the older one even though I've sudo mvn clean install the app and then build the image.
I've a docker-compose file which looks like this:
version: "3"
services:
app:
build:
context: .
dockerfile: ./docker/docker-app/Dockerfile
ports:
- "8080:8080"
links:
- "db:task_book_db"
depends_on:
- "db"
db:
image: mysql:5.7.22
command: --default-authentication-plugin=mysql_native_password
restart: always
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=sample_db
- MYSQL_USER=sample_usr
- MYSQL_PASSWORD=sample_pw
ports:
- "3306:3306"
start_dependencies:
image: dadarek/wait-for-dependencies
depends_on:
- "db"
I do sudo docker-compose run --rm start_dependencies && sudo docker-compose up --build app and whenever I've changed something, I just stop the app container then I do sudo docker-compose up --build app again. I've read about volumes but I'm not sure how to use them yet.

As mentioned in the comments:
This issue might be because of browser cache. Try accessing the 127.0.0.1:8080/static/js/myjs.js
after clearing the cache.

Docker depends_on Order Not Working

I'm trying to a selenium hub, chrome node, and firefox node, and my code that runs the test execution script in that order. I have the nodes depending on the hub and the code depending on both hubs. However, running docker-compose --build builds the code first and tries to run without starting the selenium components. I am unsure what I am doing wrong.
docker-compose.yml
version: '3'
services:
hub:
image: selenium/hub
networks:
robottestsnw: {}
ports:
- 4444:4444
chrome:
image: selenium/node-chrome
networks:
robottestsnw: {}
depends_on:
- hub
shm_size: '2g'
environment:
SCREEN_WIDTH: 1920
SCREEN_HEIGHT: 1080
HUB_HOST: hub
firefox:
image: selenium/node-firefox
networks:
robottestsnw: {}
depends_on:
- hub
shm_size: '2g'
environment:
HUB_PORT_4444_TCP_ADDR: hub
SCREEN_WIDTH: 1920
SCREEN_HEIGHT: 1080
HUB_HOST: hub
robottests:
build: .
networks:
robottestsnw: {}
depends_on:
- chrome
- firefox
networks:
robottestsnw:
driver: bridge
Dockerfile
# Dockerfile
# Base image
FROM sgrio/java-oracle
RUN apt-get update
RUN apt-get install -y maven
# Copy test project files to the image folder
COPY . /frontend-integration-tests
# Make the folder as a working directory
WORKDIR /frontend-integration-tests
# Install the test project libraries
RUN mvn package
CMD ["java", "-cp", "target/automated-testing 0.0.1-SNAPSHOT.jar", "automated-testing.service.App"]

docker-compose up
It starts services in dependency order, about docker-compose --build up don't sure. And maybe your port, network name are defined wrong:
hub:
image: selenium/hub
networks:
- robottestsnw
ports:
- 4444:4444