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01: Docker Tutorial – compile & run Helloworld.java

Docker, Jenkins, CI/CD, & DEV/OPS have been the buzz words for the last several years. You will be seeing this in more often in the job requirements as well. 21 Docker interview questions & answers | DevOps & CI/CD Interview Q&As

Pre-requisite: Docker is installed on your machine for example:

Mac OS X

$ brew cask install docker

1	$ brew cask install docker

Linux systems

# install newest version
curl -fsSL https://get.docker.com | bash

# add current user to docker group so that it can execute docker commands
sudo usermod -aG docker $USER

# Start docker
sudo systemctl start docker

# install newest version

curl -fsSL https://get.docker.com | bash

# add current user to docker group so that it can execute docker commands

sudo usermod -aG docker $USER

# Start docker

sudo systemctl start docker

Windows10

Step 1: Create a folder “

…

02: Docker Tutorial – Inspect the container

This extends the 01: Docker Tutorial – compile & run Helloworld.java. Keep the container running Docker containers are designed to shut down immediately after initial CMD or ENTRYPOINT command is run. To make it keep running you can change the last line to

CMD /app/run.sh && tail -f /dev/null

1	CMD /app/run.sh && tail -f /dev/null

Delete all stopped containers

~/projects/docker-hadoop]$ docker rm $(docker ps -a -q)

1	~/projects/docker-hadoop]$ docker rm $(docker ps -a -q)

-a...

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03: Docker Tutorial – Java & Maven with a jar file

This extends the 01: Docker Tutorial – compile & run Helloworld.java. Maven pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.myapp</groupId>
  <artifactId>helloworld</artifactId>
  <version>1.0</version>
 
  <build>
    <plugins>
      <plugin>
        <!-- Build an executable JAR -->
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.1.0</version>
        <configuration>
          <archive>
            <manifest>
              <addClasspath>true</addClasspath>
              <classpathPrefix>lib/</classpathPrefix>
              <mainClass>com.myapp.Helloworld</mainClass>
            </manifest>
          </archive>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

<groupId>com.myapp</groupId>

<artifactId>helloworld</artifactId>

<build>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-jar-plugin</artifactId>

<mainClass>com.myapp.Helloworld</mainClass>

</manifest>

</archive>

</configuration>

</plugin>

</plugins>

</build>

</project>

The run.sh file

#!/bin/bash

mvn clean package
chmod -R +x target/helloworld-1.0.jar
java -jar target/helloworld-1.0.jar

#!/bin/bash

mvn clean package

chmod -R +x target/helloworld-1.0.jar

java -jar target/helloworld-1.0.jar

Create src/main/java folder Maven requires .java files to be in the folder src/main/java folder. So create the folder and move com/myapp/* under that as shown in the above diagram. … Read more...

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03: Java gRPC with flatbuffers on Docker & Maven tutorial step by step

This extends Java gRPC with flatbuffers & Maven tutorial step by step.

The only difference in this tutorial is to use flatc via a Docker image that has flatbuffers.

This tutorial uses the image neomantra/flatbuffers from Docker hub.

…

04: Docker Tutorial – mount a host directory in a Docker container

mount a host directory into a Docker container so that the folders & files in the host will show up in the Docker container after building the dockerfile. There are a couple ways you can do this. Option 1: ADD In this approach, any changes made to this directory on...

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05: Docker Tutorial – Client & Server on separate containers & networking

In this tutorial, let’s run a Java socket client & a server in two separate Docker containers. Both the client & server are continuously run, and networked by creating a Docker network. MyClient.java

package com.myapp;

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;

public class MyClient {
    public static void main(String[] args) throws IOException {
        if (args.length != 1) {
            System.err
                    .println("Pass the server IP as the sole command line argument");
            return;
        }
        try (Socket socket = new Socket(args[0], 8888);
                Scanner sc = new Scanner(System.in);
                Scanner in = new Scanner(socket.getInputStream())) {

            OutputStream os = socket.getOutputStream();
            PrintWriter out = new PrintWriter(os);

            while (true) {
                while(sc.hasNextLine()) {
                    String msg = sc.nextLine();
                    System.out.println("Client sending: " + msg);
                    out.println(msg);
                    out.flush();

                    System.out.println("Server response: " + in.nextLine());
                }
            }
        }
    }
}

package com.myapp;

import java.io.IOException;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.Socket;

import java.util.Scanner;

public class MyClient {

public static void main(String[] args) throws IOException {

if (args.length != 1) {

System.err

.println("Pass the server IP as the sole command line argument");

return;

}

try (Socket socket = new Socket(args[0], 8888);

Scanner sc = new Scanner(System.in);

Scanner in = new Scanner(socket.getInputStream())) {

OutputStream os = socket.getOutputStream();

PrintWriter out = new PrintWriter(os);

while (true) {

while(sc.hasNextLine()) {

String msg = sc.nextLine();

System.out.println("Client sending: " + msg);

out.println(msg);

out.flush();

System.out.println("Server response: " + in.nextLine());

}

MyServer.java

package com.myapp;

import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

public class MyServer {

    public static void main(String[] args) throws IOException {
        try (ServerSocket listener = new ServerSocket(8888)) {
            System.out.println("The server is running...");
            while (true) {
                try (Socket socket = listener.accept();
                        Scanner in = new Scanner(socket.getInputStream())) {
                    PrintWriter out = new PrintWriter(socket.getOutputStream(),
                            true);
                    while (in.hasNextLine()) {
                        String msg = in.nextLine();
                        System.out.println("Server received: " + msg);
                        out.println(msg.toUpperCase());
                    }
                }
            }
        }
    }

}

package com.myapp;

import java.io.IOException;

import java.io.PrintWriter;

import java.net.ServerSocket;

import java.net.Socket;

import java.util.Scanner;

public class MyServer {

public static void main(String[] args) throws IOException {

try (ServerSocket listener = new ServerSocket(8888)) {

System.out.println("The server is running...");

while (true) {

try (Socket socket = listener.accept();

Scanner in = new Scanner(socket.getInputStream())) {

PrintWriter out = new PrintWriter(socket.getOutputStream(),

true);

while (in.hasNextLine()) {

String msg = in.nextLine();

System.out.println("Server received: " + msg);

out.println(msg.toUpperCase());

}

Dockerfile.client

FROM alpine:3.6

MAINTAINER java-success.com
 
WORKDIR /app

USER root

# install required packages
RUN apk add --no-cache openssh openssl openjdk8 rsync bash procps nss maven

# set JAVA_HOME
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
ENV PATH $PATH:$JAVA_HOME/bin

COPY src/main/java/com/myapp/MyClient.java com/myapp/MyClient.java

RUN javac com/myapp/MyClient.java

EXPOSE 8888
ENTRYPOINT ["java"]
CMD ["com.myapp.MyClient", "myserver"]

FROM alpine:3.6

MAINTAINER java-success.com

WORKDIR /app

USER root

# install required packages

RUN apk add --no-cache openssh openssl openjdk8 rsync bash procps nss maven

# set JAVA_HOME

ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk

ENV PATH $PATH:$JAVA_HOME/bin

COPY src/main/java/com/myapp/MyClient.java com/myapp/MyClient.java

RUN javac com/myapp/MyClient.java

EXPOSE 8888

ENTRYPOINT ["java"]

CMD ["com.myapp.MyClient", "myserver"]

Note that “ … Read more ›...

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06: Docker Tutorial – Spring boot application

Step 1: Go to “https://start.spring.io/“, and create a skeletal Spring project. Type “web” in the “search dependencies to add” and fill the “group” and “artifact” fields as shown below. Step 2: Click on the “+” button to add and then on the “Generate Project”, … Read more ›...

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07: Docker Tutorial – Spring boot with Docker maven plugin

This tutorial extends the 06: Docker Tutorial – Spring boot application. In the previous tutorial the Dockerfile has the jar filename & the version. Every time the version changes the Dockerfile has to be changed. Also, we have to manually type the Docker commands by opening a terminal. … Read...

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08: Docker Tutorial – client & server with docker-compose.yml

Q1. What is docker compose? A1. Docker compose allows us to configure and start multiple containers within the same host. This is handy if you don’t want to start each container separately. Q2. How does docker compose differ from Docker swarm? … Read more ›...

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Blog Archives

01: Docker Tutorial – compile & run Helloworld.java

02: Docker Tutorial – Inspect the container

03: Docker Tutorial – Java & Maven with a jar file

03: Java gRPC with flatbuffers on Docker & Maven tutorial step by step

04: Docker Tutorial – mount a host directory in a Docker container

05: Docker Tutorial – Client & Server on separate containers & networking

06: Docker Tutorial – Spring boot application

07: Docker Tutorial – Spring boot with Docker maven plugin

08: Docker Tutorial – client & server with docker-compose.yml

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