How do I call docker container using java commandline?

Question

I'm trying to run docker container from inside a java application.

Code

String[] command = {"docker exec -it test_docker java -jar test.jar"};
ProcessBuilder pb = new ProcessBuilder(command);
pb.inheritIO();
Process proc = pb.start();

While running the code I am getting an error,

Exception in thread "main" java.io.IOException: Cannot run program "docker exec -it test_docker java -jar test.jar": CreateProcess error=2, The system cannot find the file specified
        at java.lang.ProcessBuilder.start(Unknown Source)
        at com.test.company.test.RunTask.main(RunTask.java:79)
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified
        at java.lang.ProcessImpl.create(Native Method)
        at java.lang.ProcessImpl.<init>(Unknown Source)
        at java.lang.ProcessImpl.start(Unknown Source)
        ... 2 more

Here is my container list,

$ docker ps
CONTAINER ID        IMAGE                          COMMAND                  CREATED             STATUS              PORTS                                            NAMES
f37c7ae71e12        tomcat:latest                  "/usr/local/tomcat/b"   2 hours ago         Up 2 hours          0.0.0.0:8080->8080/tcp                           tomcat_docker
f2cc2579b861        java:latest                    "/bin/bash"              2 hours ago         Up 2 hours          0.0.0.0:2377->2377/tcp                           test_docker
673c6617a0d5        mysql                          "docker-entrypoint.s"   2 hours ago         Up 2 hours          0.0.0.0:53306->3306/tcp                          mysql_docker
a76ca8d8f9e4        java:latest                    "/bin/bash"              2 hours ago         Up 2 hours                                                           Client

is it possible to run docker container command using java? If possible then how do I execute using java?

Invoking a Java process within your code is not a very good way since this is not a "managed" way. Use the docker API or SDK for this purpose. Example https://docs.docker.com/develop/sdk/examples/ — Chathuranga Chandrasekara, Mar 29 '18 at 09:22
I'm not sure if you can invoke `docker commands` in your java code. One way could be executing `curl command` in code through `docker API or SDK` as @ChathurangaChandrasekara suggested. check `http` tab of the doc. reference for `curl in java`: https://stackoverflow.com/questions/24053634/using-curl-command-in-java — Abu Shumon, Mar 29 '18 at 09:54

score 3 · Answer 1 · answered Mar 29 '18 at 10:49

Try to split your command in an array like structure. as an example below

Process process;
String[] commandAndArgs = new String[]{ "/bin/sh","docker","exec","-it","test_docker","java","-jar","test.jar" };
process = Runtime.getRuntime().exec(commandAndArgs);

set Environment and Working Directory both for your process. Since the error you are getting specifies Unknown Source, It can be ENVIRONMENT problem

java.lang.ProcessBuilder.start(Unknown Source)

From Java docs you can see it states this exec() overloaded method

exec(String[] cmdarray, String[] envp, File dir)

Executes the specified command and arguments in a separate process with the specified environment and working directory.

In case nothing stated works, I request you to kindly write a shell script file for your command and then set it executable using

chmod 755 or chmod +x script.sh;

then try to run that. I hope it works

score 3 · Accepted Answer · answered Apr 13 '18 at 13:20

I have found the way through which you can run docker command inside java. There is a library available named spotify/docker-client on git docker-client using that you can run your docker command using java.It's easy to use library.

Here is a user manual docker-client user_manual

How do I call docker container using java commandline?

2 Answers2