I use openapi-generator-maven-plugin with a JSON which contains a scheme that references itself (Newtonsoft.Json.Linq.JToken). I specify that I cannot modify the JSON input.

At launch, I have StackOverflowError like this :

Exception in thread "main" java.lang.StackOverflowError
at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:446)
at java.lang.StringBuilder.append(StringBuilder.java:136)
at org.openapitools.codegen.DefaultCodegen.getPrimitiveType(DefaultCodegen.java:2370)
at org.openapitools.codegen.DefaultCodegen.getSingleSchemaType(DefaultCodegen.java:2353)
at org.openapitools.codegen.DefaultCodegen.getSchemaType(DefaultCodegen.java:2244)
at org.openapitools.codegen.languages.AbstractJavaCodegen.getSchemaType(AbstractJavaCodegen.java:1392)
at org.openapitools.codegen.languages.AbstractJavaCodegen.getTypeDeclaration(AbstractJavaCodegen.java:959)
at org.openapitools.codegen.languages.AbstractJavaCodegen.getTypeDeclaration(AbstractJavaCodegen.java:959)
at org.openapitools.codegen.languages.AbstractJavaCodegen.getTypeDeclaration(AbstractJavaCodegen.java:959)
...

Here’s the schema :

"Newtonsoft.Json.Linq.JToken": {
   "type": "array",
   "items": {
      "$ref": "#/components/schemas/Newtonsoft.Json.Linq.JToken"
   }, "nullable": true
}

In my pom.xml, the implementation of the plugin :

<plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>5.3.1</version>
                <executions>
                    <execution>
                        <id>json-production</id>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <phase>generate-sources</phase>
                        <configuration>
                            <configHelp>false</configHelp>
                            <generateApiTests>false</generateApiTests>
                            <generateModelTests>false</generateModelTests>
                            <generateApis>false</generateApis>
                            <configOptions>
                                <useSpringBoot3>true</useSpringBoot3>
                                <openApiNullable>false</openApiNullable>
                                <interfaceOnly>true</interfaceOnly>
                            </configOptions>                          
                            <inputSpec>
                                ${project.basedir}/src/main/resources/schema/openapi.json
                            </inputSpec>
                            <generatorName>spring</generatorName>
                            <apiPackage>com.api</apiPackage>
                            <modelPackage>com.dto</modelPackage>
                            <output>${basedir}/target/generated</output>
                            <globalProperties>
                                <skipFormModel>false</skipFormModel>
                            </globalProperties>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

When I replace (for tests), the reference by “type”:”string” like bellow, it works, but I can’t work with this.

"Newtonsoft.Json.Linq.JToken": {
   "type": "array",
   "items": {
      "type": "string"
   }, "nullable": true
}

I also tried to change configOptions in the pom, but I found nothing