Spring Boot: Use different Tomcat Version

Question

In Spring Boot Documentation there is a section Use Tomcat 7.x or 8.0 with Gradle This works great with Maven as shown in some spring-boot-samples, but unfortunately not for Gradle.

Is there a easier solution than excluding all tomcat dependencies form tomcat-starter and add them separately with another version?

To Reproduce: If you convert the sample project spring-boot-sample-tomcat80-ssl into a Gradle project with following dependencies:

dependencies {
    compile("org.springframework.boot:spring-boot-starter:1.4.2.RELEASE")
    compile("org.springframework.boot:spring-boot-starter-tomcat:1.4.2.RELEASE")
    compile("org.springframework:spring-webmvc:4.3.4.RELEASE")
    compile("org.apache.httpcomponents:httpclient:4.5.2")
    compile("org.apache.tomcat:tomcat-juli:8.0.36")
    compile("org.yaml:snakeyaml:1.17")
    testCompile 'org.springframework.boot:spring-boot-starter-test:1.4.2.RELEASE'
}

The output from gradlew dependencies looks like this:

compile - Dependencies for source set 'main'.
+--- org.springframework.boot:spring-boot-starter:1.4.2.RELEASE
|    +--- org.springframework.boot:spring-boot:1.4.2.RELEASE
|    |    +--- org.springframework:spring-core:4.3.4.RELEASE
|    |    |    \--- commons-logging:commons-logging:1.2
|    |    \--- org.springframework:spring-context:4.3.4.RELEASE
|    |         +--- org.springframework:spring-aop:4.3.4.RELEASE
|    |         |    +--- org.springframework:spring-beans:4.3.4.RELEASE
|    |         |    |    \--- org.springframework:spring-core:4.3.4.RELEASE (*)
|    |         |    \--- org.springframework:spring-core:4.3.4.RELEASE (*)
|    |         +--- org.springframework:spring-beans:4.3.4.RELEASE (*)
|    |         +--- org.springframework:spring-core:4.3.4.RELEASE (*)
|    |         \--- org.springframework:spring-expression:4.3.4.RELEASE
|    |              \--- org.springframework:spring-core:4.3.4.RELEASE (*)
|    +--- org.springframework.boot:spring-boot-autoconfigure:1.4.2.RELEASE
|    |    \--- org.springframework.boot:spring-boot:1.4.2.RELEASE (*)
|    +--- org.springframework.boot:spring-boot-starter-logging:1.4.2.RELEASE
|    |    +--- ch.qos.logback:logback-classic:1.1.7
|    |    |    +--- ch.qos.logback:logback-core:1.1.7
|    |    |    \--- org.slf4j:slf4j-api:1.7.20 -> 1.7.21
|    |    +--- org.slf4j:jcl-over-slf4j:1.7.21
|    |    |    \--- org.slf4j:slf4j-api:1.7.21
|    |    +--- org.slf4j:jul-to-slf4j:1.7.21
|    |    |    \--- org.slf4j:slf4j-api:1.7.21
|    |    \--- org.slf4j:log4j-over-slf4j:1.7.21
|    |         \--- org.slf4j:slf4j-api:1.7.21
|    +--- org.springframework:spring-core:4.3.4.RELEASE (*)
|    \--- org.yaml:snakeyaml:1.17
+--- org.springframework.boot:spring-boot-starter-tomcat:1.4.2.RELEASE
|    +--- org.apache.tomcat.embed:tomcat-embed-core:8.5.6
|    +--- org.apache.tomcat.embed:tomcat-embed-el:8.5.6
|    \--- org.apache.tomcat.embed:tomcat-embed-websocket:8.5.6
|         \--- org.apache.tomcat.embed:tomcat-embed-core:8.5.6
+--- org.springframework:spring-webmvc:4.3.4.RELEASE
|    +--- org.springframework:spring-aop:4.3.4.RELEASE (*)
|    +--- org.springframework:spring-beans:4.3.4.RELEASE (*)
|    +--- org.springframework:spring-context:4.3.4.RELEASE (*)
|    +--- org.springframework:spring-core:4.3.4.RELEASE (*)
|    +--- org.springframework:spring-expression:4.3.4.RELEASE (*)
|    \--- org.springframework:spring-web:4.3.4.RELEASE
|         +--- org.springframework:spring-aop:4.3.4.RELEASE (*)
|         +--- org.springframework:spring-beans:4.3.4.RELEASE (*)
|         +--- org.springframework:spring-context:4.3.4.RELEASE (*)
|         \--- org.springframework:spring-core:4.3.4.RELEASE (*)
+--- org.apache.httpcomponents:httpclient:4.5.2
|    +--- org.apache.httpcomponents:httpcore:4.4.4
|    +--- commons-logging:commons-logging:1.2
|    \--- commons-codec:commons-codec:1.9
+--- org.apache.tomcat:tomcat-juli:8.0.36
\--- org.yaml:snakeyaml:1.17

Executing the SampleTomcatSslApplicationTests you can see the wrong Tomcat Version in Logs:

2016-12-21 10:20:36.713  INFO 11368 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-12-21 10:20:36.714  INFO 11368 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.6

SOLUTION

• use spring boot gradle plugin -> here comes the magic
• set ext['tomcat.version'] = '8.0.36' in build script

Answer 1

I already replied you on the issue you've created. After you've told us our documentation was wrong, I took the time to build a sample that does exactly what is referenced in the doc.

If that does not work for you, you'll have to be more specific and explain what is wrong in the documentation.