balenalib/n510-tx2-fedora-openjdk

This image is part of the https://balena.io/?ref=dockerhub base image series for IoT devices. The image is optimized for use with https://balena.io/?ref=dockerhub and https://www.balena.io/os/?ref=dockerhub, but can be used in any Docker environment running on the appropriate architecture.

!balenalogo.

Some notable features in balenalib base images:

• Helpful package installer script called install_packages that abstracts away the specifics of the underlying package managers. It will install the named packages with smallest number of dependencies (ignore optional dependencies), clean up the package manager medata and retry if package install fails.

• Working with dynamically plugged devices: each balenalib base image has a default ENTRYPOINT which is defined as ENTRYPOINT ["/usr/bin/entry.sh"], it checks if the UDEV flag is set to true or not (by adding ENV UDEV=1) and if true, it will start udevd daemon and the relevant device nodes in the container /dev will appear.

For more details, please check the https://www.balena.io/docs/reference/base-images/base-images/#features-overview in our documentation.

https://www.balena.io/docs/reference/base-images/base-images/#run-vs-build?ref=dockerhub

The balenalib images come in many flavors, each designed for a specific use case.

:<version> or :<version>-run

This is the defacto image. The run variant is designed to be a slim and minimal variant with only runtime essentials packaged into it.

:<version>-build

The build variant is a heavier image that includes many of the tools required for building from source. This reduces the number of packages that you will need to manually install in your Dockerfile, thus reducing the overall size of all images on your system.

What is OpenJDK?

OpenJDK (Open Java Development Kit) is a free and open source implementation of the Java Platform, Standard Edition (Java SE). OpenJDK is the official reference implementation of Java SE since version 7.

***.org/wiki/OpenJDK

Java is a registered trademark of Oracle and/or its affiliates.

!https://raw.githubusercontent.com/docker-library/docs/a3439b66b7980d1811f6b3835a3c541747172970/openjdk/logo.png.

How to use this image

Start a Java instance in your app

The most straightforward way to use this image is to use a Java container as both the build and runtime environment. In your Dockerfile, writing something along the lines of the following will compile and run your project:

dockerfile
FROM balenalib/n510-tx2-fedora-openjdk:latest
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
RUN javac Main.java
CMD ["java", "Main"]

You can then run and build the Docker image:

console
$ docker build -t my-java-app .
$ docker run -it --rm --name my-running-app my-java-app

Compile your app inside the Docker container

There may be occasions where it is not appropriate to run your app inside a container. To compile, but not run your app inside the Docker instance, you can write something like:

console
$ docker run --rm -v "$PWD":/usr/src/myapp -w /usr/src/myapp balenalib/n510-tx2-fedora-openjdk:latest javac Main.java

This will add your current directory as a volume to the container, set the working directory to the volume, and run the command javac Main.java which will tell Java to compile the code in Main.java and output the Java class file to Main.class.

User Feedback

Issues

If you have any problems with or questions about this image, please contact us through a https://github.com/balena-io-library/base-images/issues.

Contributing

You are invited to contribute new features, fixes, or updates, large or small; we are always thrilled to receive pull requests, and do our best to process them as fast as we can.

Before you start to code, we recommend discussing your plans through a https://github.com/balena-io-library/base-images/issues, especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.

Documentation

Documentation for this image is stored in the https://www.balena.io/docs/reference/base-images/base-images/#balena-base-images?ref=dockerhub. Check it out for list of all of our base images including many specialised ones for e.g. node, python, go, smaller images, etc.

You can also find more details about new features in balenalib base images in this https://www.balena.io/blog/new-year-new-balena-base-images/?ref=dockerhub