feat: migrate to jackson 3

[vpelikh]

Description

This PR consists of two commits:

• update to java 17 (minimum version for jackson 3)
• update to jackson 3

Fixes: #4991

Type of Change

• 🐛 Bug fix
• ✨ New feature
• ♻️ Refactor (non-breaking change)
• 🧪 Tests
• 📝 Documentation
• 🧹 Chore (build or tooling)

Checklist

• I have added/updated tests as needed
• I have added/updated documentation where applicable
• The PR title is descriptive
• The code builds and passes tests locally
• I have linked related issues (if any)

Screenshots / Additional Context

[cbot59]

I think we need to introduce constructor for ModelResolver(JsonMapper) and deprecate the old constructor so the newer release requires user to Jackson3 instead.

currently I have such usage on ModelResolver when using springdoc-openapi

my first attempt to migrate to Jackson3 would be

public ModelResolver modelResolver(JsonMapper jsonMapper) {
        return new ModelResolver(jsonMapper);
    }

as it is more straightforward

[vpelikh]

I have removed many of the changes associated with java 17, so the PR is now much smaller.

@cbot59, thanks for the comment! JsonMapper is a descendant of ObjectMapper, so return new ModelResolver(jsonMapper); should work without a new constructor.

[WilliamAGH]

Hey everyone -- thanks to @vpelikh, we now have Jackson 3 and Java 17 support.

But I didn't want to wait, so I have it available here! His branch is available as a dependency, just add this to your build.gradle file or pom.xml equivalent:

configurations.all {
    resolutionStrategy.dependencySubstitution {
        substitute(module("io.swagger.core.v3:swagger-core-jakarta"))
            .using(module("com.github.WilliamAGH.swagger-core:swagger-core-jakarta:jackson-3-SNAPSHOT"))
        substitute(module("io.swagger.core.v3:swagger-models-jakarta"))
            .using(module("com.github.WilliamAGH.swagger-core:swagger-models-jakarta:jackson-3-SNAPSHOT"))
        substitute(module("io.swagger.core.v3:swagger-annotations-jakarta"))
            .using(module("com.github.WilliamAGH.swagger-core:swagger-annotations-jakarta:jackson-3-SNAPSHOT"))
    }

[piotrooo]

@cbot59, thanks for the comment! JsonMapper is a descendant of ObjectMapper, so return new ModelResolver(jsonMapper); should work without a new constructor.

No, it doesn't, because the ObjectMapper used by Swagger comes from the com.fasterxml.jackson.databind package (Jackson v2), while in v3 the JsonMapper comes from tools.jackson.databind.

[KP-EV]

Any update on this?

[larsf96]

Any chance that a maintainer takes a look here?
Is there any workaround to use Spring Boot 4 with SpringDoc 3 without waiting for this?

[WilliamAGH]

Any chance that a maintainer takes a look here? Is there any workaround to use Spring Boot 4 with SpringDoc 3 without waiting for this?

Yes, I’ve had this workaround in use in production for the last 2 weeks:

#5031 (comment)

[larsf96]

configurations.all {
resolutionStrategy.dependencySubstitution {
substitute(module("io.swagger.core.v3:swagger-core-jakarta"))
.using(module("com.github.WilliamAGH.swagger-core:swagger-core-jakarta:jackson-3-SNAPSHOT"))
substitute(module("io.swagger.core.v3:swagger-models-jakarta"))
.using(module("com.github.WilliamAGH.swagger-core:swagger-models-jakarta:jackson-3-SNAPSHOT"))
substitute(module("io.swagger.core.v3:swagger-annotations-jakarta"))
.using(module("com.github.WilliamAGH.swagger-core:swagger-annotations-jakarta:jackson-3-SNAPSHOT"))
}

This does not work for me:

***************************
APPLICATION FAILED TO START
***************************

Description:

An attempt was made to call a method that does not exist. The attempt was made from the following location:

    org.springdoc.core.providers.ObjectMapperProvider.<init>(ObjectMapperProvider.java:75)

The following method did not exist:

    'com.fasterxml.jackson.databind.ObjectMapper io.swagger.v3.core.util.Json31.mapper()'

The calling method's class, org.springdoc.core.providers.ObjectMapperProvider, was loaded from the following location:

    jar:file:/application/BOOT-INF/lib/springdoc-openapi-starter-common-3.0.1.jar!/org/springdoc/core/providers/ObjectMapperProvider.class

The called method's class, io.swagger.v3.core.util.Json31, is available from the following locations:

    jar:file:/application/BOOT-INF/lib/swagger-core-jakarta-jackson-3-52d4c245bb-1.jar!/io/swagger/v3/core/util/Json31.class
    jar:file:/application/BOOT-INF/lib/swagger-core-jakarta-2.2.41.jar!/io/swagger/v3/core/util/Json31.class

The called method's class hierarchy was loaded from the following locations:

    io.swagger.v3.core.util.Json31: file:/application/BOOT-INF/lib/swagger-core-jakarta-jackson-3-52d4c245bb-1.jar


Action:

Correct the classpath of your application so that it contains compatible versions of the classes org.springdoc.core.providers.ObjectMapperProvider and io.swagger.v3.core.util.Json31

[vpelikh]

@daniel-kmiecik @Mattias-Sehlstedt @ewaostrowska, hey! I see you've done the last commits to this repository. Can anyone check out this PR?

[Mattias-Sehlstedt]

Hi @vpelikh, I am only a contributor, so I can unfortunately not do anything to help. But the other two are maintainers and will hopefully assist you.

[piotrooo]

@MichakrawSB Is there any ETA for this feature? Can we please prioritize this?

[KP-EV]

It would be really great if you could prioritize this 🙏

[fenston]

Is this PR not progressing?

[lordarnoud]

Any information on this yet? Will this also make it work with the newest springboot and java 26?

[jochenberger]

I'm running the current version with latest Spring Boot/Jackson 3 on Java 26 without issues.

[piotrooo]

I'm running the current version with latest Spring Boot/Jackson 3 on Java 26 without issues.

Yes, it works. However, you probably need to add Jackson 2 compatibility support using the deprecated classes. It does work, but it is not an ideal solution.

[mzhafez]

Is there any plan on merging this or maybe adding this to the next major version instead?

[lbenedetto]

Going to be forced to ditch swagger and find another solution soon 😅

Spring Boot 3.5.x OSS Support (End of Life) ends on June 30, 2026. After this date, community-driven security patches and bug fixes will cease.

[BranislavMalo]

Hey, any update on this?

this has been open since january 1st and there’s a lot of interest here compared to most PRs, but it’s still just sitting in “review required” while multiple releases went out

is this actually planned to be merged anytime soon or is it blocked on something?

[jochenberger]

Yes, it works. However, you probably need to add Jackson 2 compatibility support using the deprecated classes.

No, you don't. Just upgrade Spring Boot and migrate your code to Jackson 3. As long as swagger-core depends on Jackson 2, they will pull it in and just use it.

I wonder how many people give up before even trying to do the update.

[zqq90]

I'm running the current version with latest Spring Boot/Jackson 3 on Java 26 without issues.

@jochenberger

I suspect you might not have used certain annotations from the jackson-databind package, such as JsonNaming.

Or you may have added both Jackson 2 and Jackson 3 annotations at the same time during the migration.

For example:

@tools.jackson.databind.annotation.JsonNaming(tools.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy.class)
@com.fasterxml.jackson.databind.annotation.JsonNaming(com.fasterxml.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy.class)
public class SampleVO {

If that's the case, it's really a nagging annoyance.

[jochenberger]

Good point @zqq90, I'm indeed not using any of those.

[KP-EV]

@ewaostrowska is it possible to prioritize this higher? Alot of teams are waiting for this :)

[EnvyIT]

Hey folks,

first of all, thanks for your work and all the continuous improvements — really appreciated.

As mentioned earlier, do you have an idea when this fix will be released or merged? At the moment, the available workarounds are quite cumbersome, and we’d really like to remove Jackson 2.x entirely from our codebase if possible.

If there’s anything we can help with to speed up the process (testing, feedback, etc.), happy to support.

Thanks a lot in advance for your time and help!

[WilliamAGH]

I've had this instance running exclusively on Jackson 3 / Spring Boot 4 for the last several months in a large production environment (the same one mentioned above 4 months ago), you're welcome to use it. It's a pretty simple fix and already available:

vpelikh/swagger-core@master...WilliamAGH:swagger-core:master

[KP-EV]

@djankows sorry for being annoying, but we are closer and closer approaching the deprecation of spring boot 3 and we would really like to do the migration :) Alot of people are waiting on this. Do you need any help?

[pikmin86]

sorry @djankows to re-up the subject but spring boot 3 ends in a month :(

[lbenedetto]

Hey guys, I've gone ahead and proceeded with upgrading to SB4 without this being fixed. I think for most people, it won't be too inconvenient. My setup looks like this:

@Configuration
public class ApiJsonConfiguration {
  @Bean
  @Primary
  public JsonMapper jsonMapper() {
    return JsonMapper.builder()
        .propertyNamingStrategy(PropertyNamingStrategies.SNAKE_CASE)
        .changeDefaultPropertyInclusion(incl -> incl.withValueInclusion(JsonInclude.Include.NON_ABSENT))
        .changeDefaultPropertyInclusion(incl -> incl.withContentInclusion(JsonInclude.Include.NON_ABSENT))
        .addModule(new SimpleModule().addSerializer(Identity.class, new IdentityToStringSerializer()))
        .addModule(new IdentityDeserializationModule())
        .build();
  }

  @Bean
  @SuppressWarnings("removal") // For now, ModelResolver from swagger-core only supports Jackson 2.x
  // In the future, swagger might support Jackson 3, and then we should just pass in the JsonMapper from above
  public ModelResolver modelResolver() {
    return new ModelResolver(new org.springframework.http.converter.json.Jackson2ObjectMapperBuilder()
        .propertyNamingStrategy(com.fasterxml.jackson.databind.PropertyNamingStrategies.SNAKE_CASE)
        .serializerByType(Identity.class, new IdentityToStringSerializerJackson2())
        .build());
  }
}

Its annoying, but you simply need to provide a jackson2 mapper to the ModelResolver, only configuring the settings relevant to Swagger (basically just the naming convention). Obviously, if you have tons of custom serialization logic, this might not be practical.

[mzhafez]

Hey guys, I've gone ahead and proceeded with upgrading to SB4 without this being fixed. I think for most people, it won't be too inconvenient. My setup looks like this:

@Configuration
public class ApiJsonConfiguration {
  @Bean
  @Primary
  public JsonMapper jsonMapper() {
    return JsonMapper.builder()
        .propertyNamingStrategy(PropertyNamingStrategies.SNAKE_CASE)
        .changeDefaultPropertyInclusion(incl -> incl.withValueInclusion(JsonInclude.Include.NON_ABSENT))
        .changeDefaultPropertyInclusion(incl -> incl.withContentInclusion(JsonInclude.Include.NON_ABSENT))
        .addModule(new SimpleModule().addSerializer(Identity.class, new IdentityToStringSerializer()))
        .addModule(new IdentityDeserializationModule())
        .build();
  }

  @Bean
  @SuppressWarnings("removal") // For now, ModelResolver from swagger-core only supports Jackson 2.x
  // In the future, swagger might support Jackson 3, and then we should just pass in the JsonMapper from above
  public ModelResolver modelResolver() {
    return new ModelResolver(new org.springframework.http.converter.json.Jackson2ObjectMapperBuilder()
        .propertyNamingStrategy(com.fasterxml.jackson.databind.PropertyNamingStrategies.SNAKE_CASE)
        .serializerByType(Identity.class, new IdentityToStringSerializerJackson2())
        .build());
  }
}

Its annoying, but you simply need to provide a jackson2 mapper to the ModelResolver, only configuring the settings relevant to Swagger (basically just the naming convention). Obviously, if you have tons of custom serialization logic, this might not be practical.

I think I speak for most people here; we realize theres a work around but supporting multiple versions of jackson isn't really ideal for any of us here.

We also recognize that we can simply use jackson 2.x in spring boot apps, but that also seems a bit unsafe as jackson 3 has been out for a year and we're unsure of whether jackson 2 will continue to receive the support that it needs, especially in these times where a CVE pops up every other day.

[vpelikh]

Hi, I've released Jackson 3 compatible version of all swagger-core dependencies under the group io.github.vpelikh.

You can find all artifacts here:
https://central.sonatype.com/search?q=io.github.vpelikh

For example, the swagger-core artifact:

<dependency>
    <groupId>io.github.vpelikh</groupId>
    <artifactId>swagger-core</artifactId>
    <version>3.0.0</version>
</dependency>

Also if you use springdoc-openapi:

<dependency>
    <groupId>io.github.vpelikh</groupId>
    <artifactId>springdoc-openapi-starter-webmvc-api</artifactId>
    <version>4.0.0</version>
 </dependency>

Hope this helps while official Jackson 3 support is being worked on!

[KP-EV]

@djankows Could we get any official clarification on the jackson3 integration? This merge request is already 6months old and it feels like there is zero progress on actually updating to jackson3. Just a small response would be great already :)