Closes gh-26461

Closes gh-26460

Closes gh-26440

Closes gh-26458

Update `BufferingApplicationStartup` to use thread safe data structures.

Prior to this commit, it was possible for calls from different threads
(for example due to request scope beans) to cause a
NoSuchElementException to be thrown.

Closes gh-25792

Closes gh-26452

Closes gh-25733

Previously, classes involved in config loading used a variety of
potentially different class loaders when calling SpringFactoriesLoader.
Some classes would use their own class loader and others would use null
which results in SpringFactoriesLoader's class loader being used.

This commit updates the config loading classes to consistently use the
resource loader's class loader.

Fixes gh-26126

Closes gh-26451

Closes gh-26450

* gh-26449:
  Polish "Use try-with-resources statement"
  Use try-with-resources statements

Closes gh-26449

See gh-26449

See gh-26449

Fixes gh-26445

Closes gh-25840

Closes gh-25839

This commit modifies the integration tests for the Maven and Gradle
image building goal and task to use a custom builder as a test harness
to verify that the plugins invoke the builder as expected.

Fixes gh-25838

Closes gh-26442

See gh-25798

Closes gh-26380

Closes gh-26379

Closes gh-26361

Closes gh-26430

Closes gh-26360

Closes gh-26427

Closes gh-26425

This commit fixes a flawed assertion that was relying on a log message
to validate the TaskExecutor is lazy. The level of the log message has
changed in framework and broke the test. We now rather check the bean
definition.

Fixes gh-26434

See gh-25817

Additional profiles were being processed after config file processing
when legacy processing was used.
This commit also restores the order in which additional profiles are added
when legacy processing is used.
Active profiles take precedence over additional profiles.

See gh-25817

* pr/25817:
  Polish "Process additional profiles before config files processing"
  Process additional profiles before config files processing

Closes gh-25817

See gh-25817

Additional profiles were being processed after config file processing
when legacy processing was used.
This commit also restores the order in which additional profiles are added
when legacy processing is used.
Active profiles take precedence over additional profiles.

See gh-25817