Enable ErrorProne checks and fix resulting findings

[marcphilipp]

• Classes with equals calling getClass() may potentially problematic.
  I made them final where they were "effectively" final by only
  having private or package-private constructors.

• I switched from LinkedList to ArrayList or ArrayDeque based on
  ErrorProne's recommendations.

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes

[sormuras]

Some of those checks do sound interesting, though, especially UnnecessaryLambda.

[vlsi]

It might be worth adding a TODO comment for such "nice to fix" so somebody could pick them later.

[marcphilipp]

I have added comments explaining my decision to disable these checks in 73e3dad.

[sormuras]

All textual updates, including in API documentation and suppressions, look reasonable.
Code changes seem to be covered by existing tests.

[vlsi]

There's https://errorprone.info/bugpattern/PackageLocation which has "suggestion" level by default, and it is probably worth having as error("PackageLocation")

[marcphilipp]

There's errorprone.info/bugpattern/PackageLocation which has "suggestion" level by default, and it is probably worth having as error("PackageLocation")

Thanks for the suggestion! Added in b8357c3

[vlsi]

By the way, Java 17 has random.nextLong(Long.MAX_VALUE). Have you considered it instead?

[sormuras]

Took me a while (too long) to find it: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/random/RandomGenerator.html#nextLong(long)