JDK 17 and Java 17

Owned by Julian Ladisch
Last updated: Jul 26, 2023
3 min read

To build Java and Grails based modules using JDK 17 and to run them under Java 17 a few changes are needed.

Please add any additional changes you notice to this page!

Goal

JDK 17 and Java 17 are the current LTS JDK and LTS Java versions since September 2021 and will receive free public updates at least until September 2027.

Currently most modules and the build environments use the previous LTS version, JDK 11 and Java 11. To reduce the maintenance burden JDK 11 and Java 11 should not be used for the next flower releases. Bug fixes and hot fixes for modules of a released flower release continue to use their initial LTS version.

Dockerfile

Copy the sample Dockerfile from https://github.com/folio-org/folio-tools/tree/master/folio-java-docker/openjdk17#sample-module-dockerfile

Note: Don't forget apk upgrade, this is needed for security patches!

Jenkinsfile

Change the buildNode from jenkins-agent-java11 to jenkins-agent-java17 .  Additionally, if

healthChkCmd = 'curl -sS --fail -o /dev/null  http://localhost:8081/admin/health || exit 1'

exists in the Jenkinsfile, change it to

healthChkCmd = 'wget --no-verbose --tries=1 --spider http://localhost:8081/admin/health || exit 1'

GitHub Actions

For projects using GitHub Actions, be sure to upgrade the version of Java used in the java-version key:

- uses: actions/setup-java@v3
  with:
    distribution: 'temurin'
    java-version: '17'

POM Files

If declared, be sure to change the Java version and source/target compilation versions.   This can be done under the main properties block:

<java.version>17</java.version>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>

Note: for this to work, be sure that the source/target versions are not overridden in the maven-compiler-plugin configuration

Dependencies

Upgrade lombok for Java 17 if the build fails with IllegalAccessError: class lombok.javac.apt.LombokProcessor, for example MODPUBSUB-242 - Getting issue details... STATUS

Upgrade mockito for Java 17 if the build fails with InaccessibleObjectException: Unable to make protected final, for example EDGPATRON-95 - Getting issue details... STATUS

Upgrade pl.project13.maven:git-commit-id-plugin for Java 17 if the build fails with Unable to make ... accessible: module java.base does not "opens java.util" to unnamed module, for example RMB-930 - Getting issue details... STATUS

Upgrade *:aspectj-maven-plugin to dev.aspectj:aspectj-maven-plugin latest version and replace <complianceLevel>11</complianceLevel> with <release>17</release>, upgrade aspectjrt and aspectjtools to 1.9.19.

Upgrade the jacoco-maven-plugin to version 0.8.7 or to a higher version.

Reflection

Some access using reflection is no longer allowed in Java 17 and causes InaccessibleObjectException. Rewrite the code to avoid reflection, examples:

Do NOT add --add-opens to  maven-surefire-plugin, the module may still fail in the Dockerfile (example: MODINVOICE-490 has linked 28 FAT-* failed integration tests).

Spring Boot v3

Migration to Spring Boot v3.0.0 How to

RMB

Upgrade example for a RAML Module Builder based module: https://github.com/folio-org/mod-login/pull/148/files

Testing on Vagrant

To use Java 17 on the provided Vagrant boxes, the following commands must be used:

# Install JDK/JRE 17
sudo apt update && sudo apt install -y openjdk-17-jdk

# Install new version of Maven, as the one provided with Ubuntu 20.04 has a bug with JDK 17
# See https://github.com/m-thirumal/installation_guide/blob/39187a6e9acff22b6800c7a407370478f1df5a77/maven/upgrade_maven.md for details
wget https://dlcdn.apache.org/maven/maven-3/3.8.6/binaries/apache-maven-3.8.6-bin.tar.gz
sudo mkdir -p /usr/local/apache-maven
sudo mv apache-maven-3.8.6-bin.tar.gz /usr/local/apache-maven
cd /usr/local/apache-maven
sudo tar -xzvf apache-maven-3.8.6-bin.tar.gz

# Add environment variables
tee ~/.profile <<- "EOF"
    export M2_HOME=/usr/local/apache-maven/apache-maven-3.8.6
    export M2=$M2_HOME/bin
    export MAVEN_OPTS="-Xms256m -Xmx512m"
    export PATH=$M2:$PATH          
EOF

# Then, to synchronize the environment variables you can restart your SSH session, or
source ~/.profile

# Check it works
mvn --version

Help

Ask on #development Slack channel if some module doesn't build or run under JDK 17 or Java 17 and there is no obvious fix.