Exploring Java 10 using Docker

On March 20, 2018, Java 10 was released and everybody wants to explore Java 10 but not everyone wants to change their development environment.

So in this blog, we will be discussing how can we use Java 10 using Docker.

This can be done by following simple steps given below:

1. Firstly, you need to install Docker. You can install Docker from the official site of Docker.
2. Open terminal.
3. Create a directory jdk10docker and move into that directory.
   [code language = “bash”]
   mkdir jdk10docker
   cd jdk10docker[/code]
4. Make a java class JdkTen.
   [code language = “bash”]
   vi JdkTen.java
   [/code]
5. Add the following code in your java class file.
   [code language = “Java”]
   public class JdkTen {
   public static void main(String[] args) {
   System.out.println(“Welcome to java 10! Enjoy exploring!”);
   while (true) {
   try {
   Thread.sleep(100000);
   } catch (Exception e) {
   }
   }
   }
   }
   [/code]
6. Make a text file with the name Dockerfile.
   [code language = “bash”]
   vi Dockerfile
   [/code]
7. Copy following code in the Dockerfile.
   [code language = “bash”]
   #using openjdk 10 as base image
   FROM openjdk:10
   #copying files from current directory from host to docker images
   COPY . .
   #Compiling JdkTen.java
   RUN javac JdkTen.java
   #executing JdkTen
   CMD [“java”, “JdkTen”]
   [/code]
8. Build docker image. It may take some time to download.
   [code language = “bash”]
   docker build -t explorejava:10.1 ~/jdk10docker
   [/code]
   Which should result in the following output:
   [code language = “bash”]
   Sending build context to Docker daemon 17.41kB
   Step 1/4 : FROM openjdk:10
   10: Pulling from library/openjdk
   2115d46e7396: Pull complete
   daa734ed5aa0: Pull complete
   801e6e5516c1: Pull complete
   8588f1af8d84: Pull complete
   916d2711f8ee: Pull complete
   7ce32ff39c36: Pull complete
   3be54ffb6c69: Pull complete
   fb555685447a: Pull complete
   Digest: sha256:3da180c49120b60bc8795660e7f90e2eb7df3a3d72f57aaa37008189138e311b
   Status: Downloaded newer image for openjdk:10
   — -> 4bb014411054
   Step 2/4 : COPY . .
   — -> 069e68b9a9d2
   Step 3/4 : RUN javac JdkTen.java
   — -> Running in 5d8a555f4dd2
   Removing intermediate container 5d8a555f4dd2
   — -> 862351887ea9
   Step 4/4 : CMD [“java”, “JdkTen”]
   — -> Running in 9d7c61e46665
   Removing intermediate container 9d7c61e46665
   — -> 936181cf1c9e
   Successfully built 936181cf1c9e
   Successfully tagged explorejava:10.1
   [/code]
9. Check for all the available docker images in your system using the following command:
   [code language = “bash”]
   docker images
   [/code]
   And you will be able to see all the available images on your system.
   [code language = “bash”]
   REPOSITORY TAG IMAGE ID CREATED SIZE
   explorejava 10.1 936181cf1c9e About a minute ago 883MB
   [/code]
10. Run your explorejava image by using image id corresponding it.
    [code language = “bash”]
    docker run 936181cf1c9e
    [/code]
    Resulting in the following output
    [code language = “bash”]
    Welcome to Java 10! Enjoy exploring!
    [/code]
11. Now open a new tab and check for available containers using the following command. Make sure you are in your jdk10docker directory.
    [code language = “bash”]
    docker ps -a
    [/code]
    Which will result in an output like this
    [code language = “bash”]
    CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
    ca7776ad7811 936181cf1c9e “java JdkTen” About a minute ago Up About a minute priceless_lamarr
    [/code]
12. Now execute the container with the corresponding container id.
    [code language = “bash”]
    docker exec -it ca7776ad7811 bash
    [/code]

And Java 10 is ready to use.
You can simply compile and run your java class or you can use Java REPL just by typing jshell.

For instance,

[code language = “bash”]

root@2228b1cf6513:/# jshell

[/code]

[code language = “bash”]

jshell> var list = List.of(1,”Java 10",12.3)

list ==> [1, Java 10, 12.3]

[/code]


Hope you liked the blog. Thanks for reading!


References:
docs.docker.com
docs.oracle.com