Difference between revisions of "GCube Java 8 migration guide"

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To migrate old ghn dev (ubuntu 8.04)  as node1.d.d4science , node4.d.d4science , node5.d.d4science, new nodes  are created :
 
To migrate old ghn dev (ubuntu 8.04)  as node1.d.d4science , node4.d.d4science , node5.d.d4science, new nodes  are created :
−
* node9-d-d4s.d4science.org
+
* node9-d-d4s.d4science.org (registry service)
 
* node4.d.d4science  
 
* node4.d.d4science  
 
* node5.d.d4science
 
* node5.d.d4science

Revision as of 10:19, 17 February 2017

This page collects the guidelines for the migration of D4Science infrastructure and the gCUbe software from Java 7 to Java 8. It also collects common issues (and their solution) experienced during the migration as reference for all gCube developers.

There are (few) documented incompatibilities between Java 7 and Java 8.

Running into one of them will require to re-factor the component and release a new version of it.

Java 8 compatibility guide: http://www.oracle.com/technetwork/java/javase/8-compatibility-guide-2156366.html

Source Code

Source Incompatibilities - TO COMPLETE

  • Detected at integration time (the component does not build)
  • animal-sniffer-maven-plugin can be used by developers to detect them at development time

Dependencies

Some third-party libraries are not compiled in Java 8 and their code is not Java 8 compatible. This is usually the case of very old versions.

  • lombok
    • not compatible: 0.11.6
    • suggested: 1.14.8

Behaviour Incompatibilities - TO COMPLETE

  • Cannot be detected at development and integration time
  • We will need to carefully test our artifacts

Other Incompatibilities - TO COMPLETE

" Moving to the latest tomcat version is not so easy. We want to stuck with the distribution provided tomcat for a lot of reasons:

backport of bug and security fixes compatibility with the apr libraries In addition to that, the javassist exceptions were a cosmetic only problem in the past, and an upgrade to a newer version of javassist was planned. " The solution proposed was

  • for gCore : updating the xerces and xml-api libraries to make the gCore services working;
  • for Smartgears: upgrade on ubuntu 14.04 all the development and production infrastructure. This should be resolved the problems manifested for the javassist and xml parsing.

JVM - TO COMPLETE

JVM memory management changed in Java 8: concept of PermGen space has been replaced by Metaspace. As consequence, startup options used in Java 7 (e.g. "-XX:MaxPermSize") rae not valid anymore in JVM 8.

Set Java 8 as the default JVM for all the development servers managed by Ansible. A new provisioning run is needed to install the new packages and reconfigure the services. On the smartgears-based nodes this can be done running the playbook(s) with the tags: jdk,tomcat

List of the nodes migrated:

  • node26.d.d4science.research-infrastructures.eu migrated (no java app running on this host)
  • node24.d.d4science.research-infrastructures.eu migrated (smartgears or ghn was not running on this host, only postgresql)
  • node27.d.d4science.research-infrastructures.eu migrated (old smartgears tomcat restarted with java8)
  • obis2.i-marine.research-infrastructures.eu alias geoserver-dev2.d4science-ii.research-infrastructures.eu migrated (no java app running on this host, only postgresql)
  • dev.d4science.org migrated (no java app running on this host, only postgresql)

To migrate old ghn dev (ubuntu 8.04) as node1.d.d4science , node4.d.d4science , node5.d.d4science, new nodes are created :

  • node9-d-d4s.d4science.org (registry service)
  • node4.d.d4science
  • node5.d.d4science

To migrate the old ghn dev (Ubuntu 9) as:

  • node11.d.d4science.research-infrastructures.eu Ubuntu 9.04 32-bit
  • node13.d.d4science.research-infrastructures.eu Ubuntu 9.04 32-bit
  • node20.d.d4science.research-infrastructures.eu Ubuntu 9.04 32-bit
  • node15.d.d4science.research-infrastructures.eu Ubuntu 9.10 64-bit

The first step has been creating a new hosts:

  • node11-d-d4s.d4science.org (replaced node11.d.d4science)

TO UPDATE 

*node12-d-d4s.d4science.org (it'll replace node13.d.d4science.research-infrastructures.eu)
*node13-d-d4s.d4science.org (it'll replace node15.d.d4science.research-infrastructures.eu)
*node14-d-d4s.d4science.org (it'll replace node20.d.d4science.research-infrastructures.eu)

References

  • Oracle releases plan

http://www.oracle.com/technetwork/java/eol-135779.html

  • Compatibility guide

http://www.oracle.com/technetwork/java/javase/8-compatibility-guide-2156366.html

  • Animal Sniffer Plugin Guide

https://blog.gvsig.org/2011/07/25/hunting-api-incompatibilities-with-the-animal-sniffer-project/

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