Closes gh-5741

Closes gh-5757

Closes gh-5446

Closes gh-5351

Closes gh-5738

Previously, the web application context was only set on the
ServletContext in a full-blown integration test or when MockMvc was
used.

This commit updates SpringApplicationContextLoader so that the context
is also set on the context in a plain web application test (one where
MockMvc is not being used). The change is a partial backport of commit
7dffb702.

Closes gh-4370

Closes gh-2953

* pr/5720:
  Remove the second parameter of substring() if possible

Closes gh-5720

Previously, the classpath would be logged in response to the
ApplicationStartedEvent. At this point, logging could be disabled
while the logging system is being initialized, or because the
log levels configured in the environment have not yet been applied.

This commit moves the logging to happen in response to an
ApplicationEnvironmentPreparedEvent by which point the logging
system has been initialized and its levels have been configured.

Closes gh-5313

Previously, SpringBootContextLoader configured the environment with the
test property sources using an ApplicationContextInitializer. This was
because TestPropertySourceUtils did not provide a method to directly
configure the environment using properties files, it had to be done
via an application context. An unwanted side-effect of this was that
the test property sources were not being configured before
ConfigFileApplicationListener examined the environment to determine the
name and locations of the files that it should be loading.

This commit takes advantage of a new method that was added to
TestPropertySourceUtils which allows properties files to be added
directly to the environment without using an application context. This
means that the use of the ApplicationContextInitializer can be removed
and the test property sources can be applied to the environment before
the application context is created.

Closes gh-5728

Closes gh-5725

Closes gh-5722

Previously, there were two problems with DevTools’ DataSource
auto-configuration:

1. It did not tolerate a context with multiple DataSources
2. It would attempt to shut down a DataSource that had not been created
   by DataSourceAutoConfiguration and, therefore, where we could not be
   sure of its configuration.

This commit updates DevToolsDataSourceAutoConfiguration so that it backs
off unless the context contains DataSourceProperties and a single
DataSource created by DataSourceAutoConfiguration. This ensures that it
can safely use DataSourceProperties to get the DataSource’s
driver class name and accurately determine if it’s an in-memory or
external database. Shutdown is only called for an in-memory database.

Closes gh-5540

* pr/5731:
  Remove duplicate words

Closes gh-5731

* pr/5727:
  Replacing StringBuffer with lock-free StringBuilder

Closes gh-5727

Closes gh-5664

Previously, spring.thymeleaf.cache was only applied to auto-configured
TemplateResolver. This commit also applies the propery to the
auto-configured ThymeleafViewResolver.

Closes gh-5395

Previously, if the filter chain threw an unhandled exception,
WebRequestTraceFilter would record a trace with a response status of
200. This occurred because response.getStatus() would return 200 as
the container had not yet caught the exception and mapped it to an
error response.

This commit updates WebRequestTraceFilter to align its behaviour with
MetricsFilter. It now assumes that the response status will be a 500
and only updates that to the status of the response if the call to the
filter chain returns successfully.

To avoid making a breaking change to the signature of the protected
enhanceTrace method, an HttpServletResponseWrapper is used to include
the correct status in the trace.

Closes gh-5331

See gh-5528

Flyway 4.0 provides support for repeatable migrations that do not
have a version. When such a migration has been performed,
MigrationInfo.getMigrationVersion() will return null and, previously,
FlywayEndpoint would fail with an NPE.

This commit updates FlywayEndpoint to use null as the version when
MigrationInfo.getMigrationVersion() returns null.

Closes gh-5700

This commit streamlines the Integration Starter by removing the file
http, ip, and stream modules as they are not always used by a majority
of apps that use Spring Integration and can also pull in other, unwanted
dependencies.

Additionally, a dependency on spring-integration-java-dsl has been
added. This makes it easy for users to configure Spring Integration
using Java configuration (the recommended approach), rather than via
XML. The Integration sample has been updated to use the DSL. Further
improvements could be made once the sample is using Java 8.

Closes gh-5528

Make RunProcessKiller final

Previously, a JVM that was forked by spring-boot:run could be orphaned
when the parent process (the Maven build) was terminated in an IDE. Note
that this doesn’t happen when spring-boot:run is invoked from a shell.

This commits add a shutdown hook that registered when RunMojo forks the
JVM. The shutdown hook attempts to kill the forked JVM’s RunProcess
rather than relying on the death of the parent process being sufficient
to also kill the child.

Closes gh-5815

Closes gh-5721

* pr/5714:
  Polish

Closes gh-5714

Rename spring-boot-starter-webservices back to spring-boot-starter-ws.
Unfortunately the starter exists in Spring Boot 1.3 so we can't rename
it without consequence.

See gh-5711