Java

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Java is a concurrent, class-based, and object-oriented programming language.

GitHub repo: https://github.com/docker-library/java

Library reference

This content is imported from the official Docker Library docs, and is provided by the original uploader. You can view the Docker Store page for this repo at https://store.docker.com/images/java.

DEPRECATED

This image is officially deprecated in favor of the openjdk image, and will receive no further updates after 2016-12-31 (Dec 31, 2016). Please adjust your usage accordingly.

The image has been OpenJDK-specific since it was first introduced, and as of 2016-08-10 we also have an ibmjava image, which made it even more clear that each repository should represent one upstream instead of one language stack or community, so this rename reflects that clarity appropriately.

Supported tags and respective Dockerfile links

For detailed information about the published artifacts of each of the above supported tags (image metadata, transfer size, etc), please see the repos/java directory in the docker-library/repo-info GitHub repo.

For more information about this image and its history, please see the relevant manifest file (library/java). This image is updated via pull requests to the docker-library/official-images GitHub repo.

What is Java?

Java is a concurrent, class-based, object-oriented language specifically designed to have as few implementation dependencies as possible. It is intended to allow application developers to “write once, run anywhere”, meaning that code that runs on one platform does not need to be recompiled to run on another.

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

wikipedia.org/wiki/Java_(programming_language)

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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:

FROM java:7
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
RUN javac Main.java
CMD ["java", "Main"]

You can then run and build the Docker image:

$ 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:

$ docker run --rm -v "$PWD":/usr/src/myapp -w /usr/src/myapp java:7 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.

Why is this only OpenJDK/OpenJRE?

As all of the major upstream Linux distributions are unwilling to redistribute Oracle Java in their own distribution channels, we have chosen to follow them. See references below on how each distribution does not distribute Oracle Java.

  • Ubuntu stopped distributing it in the sun-java6 package when Oracle retired the “Operating System Distributor License for Java” (lists.ubuntu.com).
  • Debian requires users to download the Java tar manually from oracle.com and then use java-package to install it (wiki.debian.net).
  • The webupd8 PPA for Ubuntu and Debian requires the user to accept the Oracle license in order for their software to download and install Oracle java (webupd8.org).
  • Gentoo has a fetch-restriction that requires the user to go to the Oracle website to download the Java tar manually which inclues accepting the license (wiki.gentoo.org).
  • CentOS requires users to go and download the rpm provided by Oracle at java.com and thus accept the Oracle license (wiki.centos.org).
  • RedHat provides instructions to add a repo that is maintained by Oracle (access.redhat.com).

Image Variants

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

java:<version>

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of. This tag is based off of buildpack-deps. buildpack-deps is designed for the average user of docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.

java:alpine

This image is based on the popular Alpine Linux project, available in the alpine official image. Alpine Linux is much smaller than most distribution base images (~5MB), and thus leads to much slimmer images in general.

This variant is highly recommended when final image size being as small as possible is desired. The main caveat to note is that it does use musl libc instead of glibc and friends, so certain software might run into issues depending on the depth of their libc requirements. However, most software doesn’t have an issue with this, so this variant is usually a very safe choice. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images.

To minimize image size, it’s uncommon for additional related tools (such as git or bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the alpine image description for examples of how to install packages if you are unfamiliar).

License

View license information for the software contained in this image.

Supported Docker versions

This image is officially supported on Docker version 17.04.0-ce.

Support for older versions (down to 1.6) is provided on a best-effort basis.

Please see the Docker installation documentation for details on how to upgrade your Docker daemon.

User Feedback

Issues

If you have any problems with or questions about this image, please contact us through a GitHub issue. If the issue is related to a CVE, please check for a cve-tracker issue on the official-images repository first.

You can also reach many of the official image maintainers via the #docker-library IRC channel on Freenode.

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 GitHub issue, 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 java/ directory of the docker-library/docs GitHub repo. Be sure to familiarize yourself with the repository’s README.md file before attempting a pull request.

library, sample, Java