OpenJDK 9 for Fedora/EPEL

Looking to try out OpenJDK 9? If you didn’t know, OpenJDK 9 is going to be the reference implemtation for Java 9 (assuming the pattern for Java 7 and Java 8 continues). Pre-release packages for Fedora 23, 24, 25 and Rawhide as well as RHEL 7 are available on copr :

https://copr.fedoraproject.org/coprs/omajid/openjdk9/

Please note that these are not official Fedora (or RHEL) packages. Official Fedora packages will be proposed and added to Fedora closer to OpenJDK 9’s release.

To install on Fedora:

# dnf copr enable omajid/openjdk9
# dnf install java-9-openjdk-devel

To install on RHEL (or CentOS) 7:

$ wget https://copr.fedorainfracloud.org/coprs/omajid/openjdk9/repo/epel-7/omajid-openjdk9-epel-7.repo
$ su -
# cp omajid-openjdk9-epel-7.repo /etc/yum.repos.d/
# yum install java-9-openjdk-devel

Then use as follows:

$ /usr/lib/jvm/java-1.9.0-openjdk/bin/java -version

To make it the default Java version, use update-alternatives.

# update-alternatives --config java
# update-alternatives --config javac

If you are a user, making 9 the default may not be a great idea - OpenJDK 9 is in heavy development and lots of things are changing. There are also some known compatibility issues. On the other hand, if you are a Java developer, this will give you a good idea of how prepared your favourite libraries and tools are for Java 9.