check "--enable-preview" flag in ${maven.compiler.enablePreview}

[RussiaVk]

check "--enable-preview" flag in ${maven.compiler.enablePreview}:
```<properties>
	<maven.compiler.enablePreview>true</maven.compiler.enablePreview>
</properties>
```

[HannesWell]

Thanks for this contribution.
Before we can accept it you have to (electronically) sign the Eclipse Contributor Agreement (ECA):
https://www.eclipse.org/legal/ecafaq.php

In general it looks good. Just one required adjustments below.

Futhermore we need a test-case to demonstrate that this new feature works now and in the future. Can you please add a little case in org.eclipse.m2e.jdt.tests.JavaConfigurationTest that has the new enablePreview property set. Ideally also test cases for the first and second way to enable preview features would be added, because I haven't found any.
Creating them should be relatively simple as it was done e.g. in 75f25ab.

[github-actions]

Test Results

107 files  ±0  107 suites  ±0   11m 33s ⏱️ + 1m 39s
662 tests +1  652 ✔️ +1  10 💤 ±0  0 ❌ ±0 
662 runs  +1  651 ✔️ +1  11 💤 ±0  0 ❌ ±0 

Results for commit d206d5c. ± Comparison against base commit 8fe2220.

♻️ This comment has been updated with latest results.

[RussiaVk]

Thanks for this contribution. Before we can accept it you have to (electronically) sign the Eclipse Contributor Agreement (ECA): https://www.eclipse.org/legal/ecafaq.php

In general it looks good. Just one required adjustments below.

Futhermore we need a test-case to demonstrate that this new feature works now and in the future. Can you please add a little case in org.eclipse.m2e.jdt.tests.JavaConfigurationTest that has the new enablePreview property set. Ideally also test cases for the first and second way to enable preview features would be added, because I haven't found any. Creating them should be relatively simple as it was done e.g. in 75f25ab.

Hello, could you please assist me in reviewing the code and kindly point out any errors if they are present?

[HannesWell]

Please see the comments about the code blow.

Furthermore you still need to electronically sign the Eclipse Contributor Agreement (ECA):

• https://accounts.eclipse.org/user/eca
• https://www.eclipse.org/legal/ECA.php

[RussiaVk]

Please see the comments about the code blow.

Furthermore you still need to electronically sign the Eclipse Contributor Agreement (ECA):

• https://accounts.eclipse.org/user/eca
• https://www.eclipse.org/legal/ECA.php

There seems to be an error in jenkins, how to fix it?

[mickaelistria]

ECA signature seems fine now.
The remaining issue that is probably related to this change is https://ci.eclipse.org/m2e/job/m2e/job/PR-1555/19/testReport/org.eclipse.m2e.jdt.tests/JavaConfigurationTest/testComplianceVsEnablePreviewSettings/

[mickaelistria]

Thanks, this looks good to me.
Reminder to whoever will merge: please use "Squash and Merge"

[HannesWell]

Looks good for me as well.
Thank you for this nice contribution, it will be part of the 2023-12 Eclipse Simulations release.