GCube Java 8 migration guide

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.

NOTE

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

Running into one of them will require to refactor 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

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

Behaviour Incompatibilities

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

JVM

JVM memory management changed in Java 8: concept of PermGen space has been replaced by Metaspace.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.

TODO: not enough results to provide guidelines and instructions

References

• Oracle releases plan

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

• New features in Java 8
  • http://www.oracle.com/technetwork/java/javase/8-whats-new-2157071.html
  • https://leanpub.com/whatsnewinjava8/read

• 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/