Installing Oracle Java

Using java requires having grsec play nice with the binaries. You may also want to install the JDK instead of the JRE depending on your needs.

This guide assumes you're running as root.

Download XXX-XXX-linux-x64.tar.gz from either the JRE or JDK section here: https://www.oracle.com/technetwork/java/javase/downloads/index.html

mkdir -p /opt/java
cd /opt/java
sudo tar -zxvf XXX-XXX-linux-x64.tar.gz 

Take note of the directory, e.g. /opt/java/jdk1.8.0_121, create a symbolic link as the current version:

ln -s /opt/java/jdk1.8.0_121 /opt/java/current

Create a file in /etc/profile.d/java.sh:

export JAVA_HOME=/opt/java/current
export PATH=$PATH:$JAVA_HOME/bin

Execute this script or restart your shell:

sh /etc/profile.d/java.sh

Now we need manage grsec with paxctl. Use this command to check if its installed:

which paxctl

If nothing comes up install it:

apk add paxctl

Now in your /opt/java/XXX/bin folder, execute:

paxctl -c java
paxctl -m java

If you have the JDK, you need to do the same to javac:

paxctl -c javac
paxctl -m javac

You can do this for any other binary you need to use.

NOTE: some users have reported they had to use this command to get it working:

setfattr -n user.pax.flags -v "mr" java
setfattr -n user.pax.flags -v "mr" javac

Alternative installation of Oracle Java on Linux Alpine

• Native Java Debugging on Alpine Linux: GDB, OpenJDK and the Mysterious Unknown Signal Shahar Valiano 2019