What’s New in Spring Boot 2.5.5? Key Fixes, Docs Updates, and Dependency Upgrades

On September 23, the official Spring Boot 2.5.5 release was announced, bringing 41 bug fixes, documentation improvements, and dependency upgrades.

Release Notes

<code>&lt;parent&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
  &lt;version&gt;2.5.5&lt;/version&gt;
  &lt;relativePath/&gt; <!-- lookup parent from repository -->
&lt;/parent&gt;
</code>

Bug Fixes

Endpoint no longer fails to clean SPRING_APPLICATION_JSON by default #28081

Flyway and Spring Integration DataSource initialization failures under non‑null mode #28079

Web MVC metrics may report incorrect status when filters throw exceptions other than NestedServletException #28069

Embedded Undertow throws MalformedURLException when URL contains special characters #28032

Concurrent image builds cause errors when deleting builder images #27993

War deployment on standalone Tomcat leads to memory leaks

IndexOutOfBoundsException when running Zip64 jar larger than 4 GB #27900

Azure App Service not correctly detected on Windows #27819

@MockBean combined with @Repeat triggers errors #27798

NullPointerException in RoutingDataSourceHealthContributor when routing datasource target is null #27698

Documentation Adjustments

Devtools restart does not work when using AspectJ weaving #28083

Default value for spring.data.elasticsearch.client.reactive.endpoints not documented #28072

Selenium auto‑configuration requires HtmlUnit #27943

Documenting java compiler -parameters usage in spring-boot-starter-parent #27885

Fix inconsistent developer tools documentation #27876

Correct typos in javadoc #27873

Document how to use WebTestClient to parameterize REST Docs output directory #27803

Add Java 17 documentation support #26767

Dependency Upgrades

Ehcache3 upgraded to 3.9.6 #27974

Glassfish EL upgraded to 3.0.4 #27975

Groovy upgraded to 3.0.9 #27976

Gson upgraded to 2.8.8 #27977

Jackson Bom upgraded to 2.12.5 #27978

Jetty EL upgraded to 9.0.52 #27979

jOOQ upgraded to 3.14.15 #28088

Kotlin upgraded to 1.5.31 #28089

Kotlin Coroutines upgraded to 1.5.2 #27982

Lettuce upgraded to 6.1.5.RELEASE #28031

Logback upgraded to 1.2.6 #27983

Maven War Plugin upgraded to 3.3.2 #27984

Micrometer upgraded to 1.7.4 #27916

Netty upgraded to 4.1.68.Final #27985

Netty tcNative upgraded to 2.0.43.Final #27986

Reactor upgraded to 2020.0.11 #27914

SendGrid upgraded to 4.7.5 #28109

Spring Data upgraded to 2021.0.5 #27917

Spring Framework upgraded to 5.3.10 #27915

Spring HATEOAS upgraded to 1.3.4 #27970

Spring Integration upgraded to 5.5.4 #27949

Spring Kafka upgraded to 2.7.7 #27918

Tomcat upgraded to 9.0.53 #27963