Also gives the user the option to override (by setting
endpoints.health.sensitive=false).

Fixes gh-1977 in a slightly different way

Spring MVC drives the postHandle method on any interceptors after the
response has been sent to the client. This meant that there was a
race between the test receiving the response and asserting that the
interceptor had been driven and Spring MVC driving the interceptor.

This commit updates the interceptor to use a CountDownLatch to track
whether or not it's been called. The test now waits for up to 30
seconds for the latch to be decremented.

Closes gh-1997

Closes gh-1989

In a properties file, a backslash is used as an escape character for
the line terminator sequence to allow values to be split across
multiple lines. When a backslash is used elsewhere they're stripped
out of the property's value.

This commit updates .properties-based examples for configuring
server.tomcat.internal-proxies to escape the backslahes so that they
are retained in the property's value at runtime.

See gh-1989

Closes gh-1998

Closes gh-1978

By default, when /health is accessed anonymously, the details are
stripped, i.e. the response will only indicate UP or DOWN. Furthermore
the response is cached for a configurable period to prevent a denial
of service attack.

This commit adds a configuration property,
endpoints.health.restrict-anonymous-access, that can be set to false
to allow full anonymous access to /health. When full access is
allowed, the details will be included in the response and the response
will not be cached.

Closes gh-1977

Previously, TestInterceptor used an int to keep a count of how often
it had been called. The count was incremented on one thread and
read on another thread. This lead to intermittent test failures as the
field was not declared volatile and a stale value would sometimes be
returned.

This commit updates TestInterceptor to use an AtomicInteger that's
held in a final field. This ensures that getCount() will not return
stale values and also ensures that the count can safely be incremented
concurrently.

Closes gh-1997

Closes gh-1908

Closes gh-1761

Closes gh-1993

Closes gh-1992

Closes gh-1969

Unlike the Tomcat and Jetty starters, the Undertow starter does not
provide an EL implementation. This leads to failures when you try to use
Hibernate Validator with the Undertow starter.

To bring the Undertow starter into line with the other two embedded
container starters, this commit adds Glassfish’s EL implementation to
the Undertow starter. This is the implementation that’s used by the
Jetty starter. If/when Undertow provides JSP support and, therefore,
starts using EL itself, we should align with it.

Closes gh-1979

Previously, index.html used absolute paths to load its CSS and
JavaScript. This meant that it had to be deployed to /. This commit
updates the HTML to use relative paths for its CSS and JavaScript,
thereby ensuring that they can be loaded irrespective of the context
path to which the application is deployed.

Closes gh-1988

Fixes gh-1986

That way, if there is one, it will always be the right one
(otherwise you might be processing teh parent context with
metadata from the child).

Fixes gh-1982

If you inject the class (via a servlet parameter) it seems that
Jersey tries to create all the beans for you (and fails). I thought
it was supposed to work (according to the docs), so I'm a bit confused
but the sample now has Spring DI and the tests pass.

Fixes gh-1981

Update the ConfigurationMetadataAnnotationProcessor nested class
algorithm to prevent inner classes being added as both groups and
properties.

Fixes gh-1975

See gh-1970

Fixes gh-1972

Previously, an Enum that is defined as an inner class of a
@ConfigurationProperties pojo was wrongly detected as an nested group.

This case is now handled explicitly and covered by a test.

Fixes gh-1971

Add a companion module that IDE developers can use to read configuration
metadata from multiple sources into a single repository.

ConfigurationMetadataRepository provides access to groups and items as
well as an harmonized view on "sources" (that is the POJOs that have
contributed to a given group).

Closes gh-1970

Fixes gh-1951

Guard against Spring Data REST TypeConstrained Jackson converters
replacing the default MappingJackson2HttpMessageConverter.

Fixes gh-1968

Update HttpMessageConvertersAutoConfiguration to only register Gson
support when Jackson is not on the classpath.

Fixes gh-1967

Rename mongo to mongodb.

Fixes gh-1966