Use Java Runtime 11 with Neo4J 3.5.x
Neo4j 3.5.x supports Java 11 as runtime, however custom code should still be compiled against Java 8. As a best practice, it is recommended to maintain your infrastructure environment on supported components (Hypervisor, Operating System, Java Virtual Machine). In this example, we will show you how to upgrade the Java JDK from version 8 to Java JDK 11 on Linux.
Java JDK 11 Installation
The first step is to install Java 11, you can refer to your preferred vendor instructions. We recommend to use a JDK to be able to run Neo4j in production. Java diagnostic commands might be required when engaging Neo4J support:
neo4j-admin reportcommand requires a JDK.
jmapdumps the heap memory into a file which can be requested to troubleshoot issues.
jfr: profiling tool used to gather diagnostics and profiling data from a running Java application. It is available for free since java 11.
At this stage, Java 8 will still be used. It is allowed to have multiple JVM installations on the same machine.
java -version will still display Java 8.
Switch to Java 11 as default
To use Java 11 runtime by default,
For RedHat, CentOS, Fedora, Amazon AMI: run
sudo alternatives --config java
For Debian-based systems, Debian, Ubuntu, Suse: run
sudo update-alternatives --config java
Pick the right version and press enter. There are 2 installed binaries that provides 'java' in this example:
$ sudo alternatives --config java Selection Command 1 java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-126.96.36.199.b09-2.amzn2.0.1.x86_64/jre/bin/java) 2 /usr/lib/jvm/java-11-amazon-corretto/bin/java
Choose the second option and press enter to validate.
java -version should now display Java 11.
Comment or remove the following line:
dbms.logs.gc.options=-XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCApplicationStoppedTime -XX:+PrintPromotionFailure -XX:+PrintTenuringDistribution
Uncomment the following setting:
You will immediately see WARNING messages in your neo4j.log You can safely disregard them as shown below:
WARNING: Please consider reporting this to the maintainers of org.eclipse.collections.impl.utility.ArrayListIterate WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release
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