Add an additional lines after the copyright header and before the
`package` declaration. This aligns with the style used by Spring
Framework.
Issue gh-8945
Replace static imports with class referenced methods. With the exception
of a few well known static imports, checkstyle restricts the static
imports that a class can use. For example, `asList(...)` would be
replaced with `Arrays.asList(...)`.
Issue gh-8945
Migrate Mockito imports to use the BDD variant. This aligns better with
the "given" / "when" / "then" style used in most tests since the "given"
block now uses Mockito `given(...)` calls.
The commit also updates a few tests that were accidentally using
Power Mockito when regular Mockito could be used.
Issue gh-8945
Apply an Eclipse cleanup rules to ensure that fields are always accessed
using `this.`. This aligns with the style used by Spring Framework and
helps users quickly see the difference between a local and member
variable.
Issue gh-8945
Update classes that have private constructors so that they are also
declared final. In a few cases, inner-classes used private constructors
but were subclassed. These have now been changed to have package-private
constructors.
Issue gh-8945
