Spring-boot: Verify spring-boot-actuator /health serialization error with jackson-2.9.0

[molexx]

Attempting to browse to /health returns a HTTP 406 'Not Acceptable', with the following error in the console:

.c.j.MappingJackson2HttpMessageConverter : Failed to evaluate Jackson serialization for type [class org.springframework.boot.actuate.health.Health]: java.lang.IllegalStateException: Can not override serializer  
.w.s.m.s.DefaultHandlerExceptionResolver : Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: (was java.lang.NullPointerException) (through reference chain: org.springframework.boot.actuate.health.Health["[anySetter]"]->java.util.Collections$UnmodifiableMap["diskSpace"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: org.springframework.boot.actuate.health.Health["[anySetter]"]->java.util.Collections$UnmodifiableMap["diskSpace"])

How to recreate:

start with 'Building a RESTful Web Service' from https://spring.io/guides/gs/rest-service/
add spring-actuator by adding to build.gradle:
compile("org.springframework.boot:spring-boot-starter-actuator")
run and test by visiting http://localhost:8080/health - should see some JSON with health info.

force upgrade to the latest snapshot version of jackson, 2.9.0, by amending build.gradle:

repositories {
    mavenCentral()
    maven {
        url "https://oss.sonatype.org/content/repositories/snapshots"
    }
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web") {
        exclude group: 'com.fasterxml.jackson.core'
    }
    testCompile('org.springframework.boot:spring-boot-starter-test')

    compile("org.springframework.boot:spring-boot-starter-actuator") {
        exclude group: 'com.fasterxml.jackson.core'
    }

    compile group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: '2.9.0-20161214.215532-368'
    compile group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: '2.9.0-20161209.054204-56'
    compile group: 'com.fasterxml.jackson.core', name: 'jackson-annotations', version: '2.9.0-20161128.053707-86'
}

re-run and see the error by visiting /health
The /greeting endpoint works as before and serializes the 'Greeting' object to JSON.

[philwebb]

Thanks for the report, we won't be officially supporting Jackson 2.9 until Spring Boot 1.5.

[philwebb]

Looking at the release schedule we're unlikely to support Jackson 2.9 until Spring Boot 2.0

[wilkinsona]

This appears to be a bug in Jackson. I've opened https://github.com/FasterXML/jackson-databind/issues/1559

[borislopezaraoz]

I see this issue even with jackson 2.9.0.pr1.
I had to use version 2.8.7:

ext {
    jacksonVersion = '2.8.7'
}

configurations.all {
    resolutionStrategy {
        force "com.fasterxml.jackson.core:jackson-core:${jacksonVersion}"
        force "com.fasterxml.jackson.core:jackson-annotations:${jacksonVersion}"
        force "com.fasterxml.jackson.core:jackson-databind:${jacksonVersion}"
    }
}