Dropping support for Java 8

[monperrus]

We're discussing dropping the support for Java 8, triggered by some incompatibilities in the latest version of JDT (#4161)

What does dropping support for Java 8 mean in our context?

• not running with JVM 8 in CI
• having some tests / contracts ignored when run on Java 8
• not being able to use more recent versions of Spoon on JVM 8 (bytecode incompatibility)
• not being able to analyze Java 8 code This is not what we we mean, since we do support old versions of Java, eg Java 1.4.

[surli]

So for information I asked for a bit more info because we are apparently still not able to entirely used Java 11 to build XWiki, there's a forum thread to follow it up: https://forum.xwiki.org/t/move-to-java-11-for-building-xwiki/7342/4

It should be fixed in a near future for us, so it might not be that much a blocker to keep using Spoon.

[slarse]

To define precisely what we mean by dropping support for Java 8 (and 9 and 10), it's that:

1. It will not be possible to build Spoon with a JDK < 11
2. It will not be possible to run Spoon in a JVM < 11

That is completely independent of what source code Spoon can be used to analyze and transform, but it does mean that projects running on anything less than Java 11 cannot use Spoon without some potentially awkward workarounds.

It should also be mentioned that we don't really have a choice in this. JDT's latest release is binary-incompatible with anything less than Java 11. We must upgrade the version of JDT to be able to get the latest Java features (for 17 and beyond). While we can push this until it's time to start implementing Java 17 features, we must inevitably up to Java 11 quite soon.

[monperrus]

It should be fixed in a near future for us, so it might not be that much a blocker to keep using Spoon.

good news!

[monperrus]

That's done, Java 8 is not supported anymore as of d54673c