* pr/2901:
  Add Freemarker `prefer-file-system-access` support

Add a `spring.freemarker.prefer-file-system-access` property and update
FreeMarkerAutoConfiguration to support it.

Fixes gh-2901

Closes gh-3308

Closes gh-3299

* pr/3297:
  Prevent restart when META-INF/maven/** changes

These files are modified by Eclipse for some reason when you change files
like Thymeleaf HTML files. `META-INF/maven/**` has been added to the
default exclusion.

Closes gh-3295
Closes gh-3297

* pr/2764:
  Add `spring.pid.fail-on-write-error` support

Update `ApplicationPidFileWriter` to support a 'fail on write error'
properties which allows the user to exit the application if the PID
file cannot be written.

This commit also deprecates `spring.pidfile` in favor of
`spring.pid.file` so that the new property can be added without overlap.

Fixes gh-2764

* pr/2804:
  Document jOOQ support
  Add jOOQ sample application
  Add support for jOOQ

Closes gh-2804

See gh-2804

Add auto-configuration and a starter POM for jOOQ.

See gh-2804

Previously, when an exception was thrown by a Controller in an
application deployed to a servlet container the exception that was
handled would be Spring Framework’s NestedServletException rather than
the exception thrown by the application. Furthermore, when an exception
was thrown or the response was used to send an error, the
javax.servlet.error.request_uri request attribute would not be set. This
differed from the behaviour in an executable jar/war where the exception
would be the one thrown by the application, and the request_uri
attribute would be set.

This commit updates ErrorPageFilter, which is only involved in a servlet
container, to unwrap a NestedServletException so that it’s the
application’s exception that’s handled, and to set the request_uri
attribute in the event of an exception being thrown or an error being
sent.

Closes gh-3249

Closes gh-3027

Previously, an address that ended in a "/" would result in the virtual
host being an empty string. This was inconsistent with setVirtualHost
which would map an empty string to "/".

This commit updates the address parsing logic to call setVirtualHost
rather than assigning the value directly to this.virtualHost. This
ensures that the special handling for an empty string is applied
consistently.

Closes gh-3304

By default, SpringApplication attempts to deduce the application class
by looking for a main method in the stack. This does not work when
the application is launched by a servlet container via
SpringBootServletInitializer as there's either no main method in the
stack, or the main method is that of the servlet container, rather
than the application.

This commit updates SpringBootServletInitializer to configure the
main class of the SpringApplication that it creates to be the
application's SpringBootServletInitializer subclass. This is done
prior to calling configure, so the main class can still be specified
by the application if required.

Closes gh-3061

Closes gh-3289

See gh-3286

Closes gh-3206

Closes gh-3246

Closes gh-2318

Previously, spring-boot required org.json:json to be on the compile
classpath, but it was only there by virtue of it being a transitive
dependency of another of spring-boot’s dependency. This commit makes
it clear that spring-boot has an (optional) dependency on org.json:json
by having an explicit dependency declaration for it. Additionally, the
name of the version property and the alphabetical ordering in
spring-boot-dependencies have been corrected.

Closes gh-3290