Switch to Java 11

[ljacqu]

Not planning to switch soon, but to keep some improvements/adjustments that we could make after switching:

• See comments in code referencing this issue
• Use List.of and Set.of where appropriate instead of more verbose Arrays.asList, etc.
• !Optional.isPresent = Optional.isEmpty
• collect(toList()) -> Stream#toList
• Upgrade to Mockito 5
• Remove Mockito exclusion from dependabot.yml

[gamerover98]

Hi, updating to Java 11 just to use these methods doesn't make much sense. Additionally, compatibility with Java 8 is more important in my opinion, as there are older projects that require the use of this JDK version.

However, if there is a way to create a second Jar file that is compatible with Java 8, as they do, for example, with HSQLDB, then you can proceed with the modification.

<dependency>
    <groupId>org.hsqldb</groupId>
    <artifactId>hsqldb</artifactId>
    <version>2.7.1</version>
    <classifier>jdk8</classifier>
    <type>jar</type>
</dependency>

Thank you.