* pr/17875:
  Remove redundant code

Closes gh-17875

See gh-17875

* pr/17874:
  Use hasSize() assertion in favor of length checks

Closes gh-17874

See gh-17874

Closes gh-17889

* pr/17861:
  Map non-null LDAP properties

Closes gh-17861

The userDn and password in LdapContextSource are not nullable. The
default values for userDn and password in LdapProperties are null. When
the values are set to null there will eventually be a
NullPointerException during
AbstractContextSource#setupAuthenticatedEnvironment since HashTable
doesn't allow null for values.

See gh-17861

Closes gh-17887

* pr/17805:
  Polish "Set up SpringLiquibase beans' dependencies by type rather than name"
  Add missing javadoc
  Set up SpringLiquibase beans' dependencies by type rather than name

Closes gh-17805

See gh-17805

See gh-17805

See gh-17805

SecurityMockMvcConfigurer now honors filter order so we can use that instead
of manually adding the filter.

Closes gh-17883

* gh-17876:
  Test the Gradle Plugin against Gradle 5.6

Closes gh-17876

See gh-17876

* pr/17871:
  Polish "Add properties for Jetty threadpool"
  Add properties for Jetty threadpool

Closes gh-17871

See gh-17871

See gh-17871

Closes gh-17880

* pr/17780:
  Polish "Expand documentation on remote devtools"
  Expand documentation on remote devtools

Closes gh-17780

See gh-17780

See gh-17780

See gh-16691

Closes gh-17878

Fixes gh-16691

* pr/17864:
  Delete redundant variables

Closes gh-17864

See gh-17864

See gh-17562

* pr/17860:
  Polish "Simplify some code"
  Simplify some code

Closes gh-17860

See gh-17860

See gh-17860

* pr/17852:
  Simplify some code

Closes gh-17852

See gh-17852

* pr/17847:
  Replace Collection#addAll to call constructor

Closes gh-17847

See gh-17847

* pr/17837:
  Simplify some code

Closes gh-17837

See gh-17837