Pulsar: The project does not build with JDK 12.

[annubiz]

Is your feature request related to a problem? Please describe.
Pulsar does not build with JDK 12. It requires JDK 1.8.
JDK 1.8 will end of life in Dec 2020. That is a year and a half away, but conversion may take a while.

Describe the solution you'd like
Please start an effort (branch) to support JDK 12

Describe alternatives you've considered
OpenJDK

Additional context
Many many many systems still use 1.8 and will for potentially yrs. It can be very difficult to support a mission critical system that uses several different jre versions. You may need to start to support 12 soon and continue to support 8 and 12 for several years.

[merlimat]

@annubiz We do support JDK 11, (even though the unit tests are not completely passing, mostly due to Mockito and Powermock issues), though we haven't started to check with JDK 12.

It would be good to have a Jenkins pipeline with JDK 12 setup for 2.5 release

[leonidv]

I've run Apache Pulsar 2.4.1 in standalone mode on open-jdk-13:

07:28:28.461 [main] INFO org.apache.zookeeper.server.ZooKeeperServer - Server environment:host.name=lv-linux 07:28:28.461 [main] INFO org.apache.zookeeper.server.ZooKeeperServer - Server environment:java.version=13 07:28:28.461 [main] INFO org.apache.zookeeper.server.ZooKeeperServer - Server environment:java.vendor=N/A 07:28:28.461 [main] INFO org.apache.zookeeper.server.ZooKeeperServer - Server environment:java.home=/usr/lib/jvm/java-13-openjdk

I've remove -XX:+AggressiveOpts from PULSAR_GC

[codelipenghui]

@annubiz Is @leonidv's comment can help? Move it to 2.7.0 first, feel free to move it back if it needs to onboard 2.6.0 release.