Upgrade to Gradle 7

[excolo-rick]

Describe the bug
Project and samples are not buildable in Java 17 due to Gradle 7 requirement and deprecation/removal of compile dependency syntax.

To Reproduce
Open project in environment running J17, and update gradle-wrapper.properties to a J17-supported version, e.g 7.3.2

Expected behavior
The project to be usable in an up-to-date environment.

Cause
The compile instruction was deprecated in Gradle 6, per https://docs.gradle.org/current/userguide/upgrading_version_5.html

It was removed from Gradle 7, and 7.3 is required for Java 17.

Solution
Change all compile instructions in gradle dependancy lists to implementation (and all testCompile to testImplementation). There are a few other changes per the upgrade instructions, but I didn't see instances of them in the checked files. This change will not adverssely impact earlier-version users as it's to bring in line with Gradle 6 deprecation.

[jgrandja]

Thanks for the request @think-info.

FYI, this project depends on Spring Security 5.5, which compiles against JDK 1.8.

We do plan on upgrading to Gradle 7 soon.

[VonUniGE]

Upgrading to Gradle 7 is not yet possible because of the spring-build-conventions dependency. The development of this plugin seems to have stopped. Last commit is dated from 29 June 2021.

Should this plugin still be used ?

See also this issue: spring-gradle-plugins/spring-build-conventions#95

[jgrandja]

@VonUniGE We have a few changes that need to be made, including spring-build-conventions, before we can upgrade to Gradle 7. I've scheduled this for next release.