ClassCastException when used along with wiremock-spring-boot:4.0.8

[salat-23]

Spring cloud version 2025.1.0
When using @AutoConfigureStubRunner from org.springframework.cloud:spring-cloud-starter-contract-stub-runner, if you have org.wiremock.integrations:wiremock-spring-boot:4.0.8 in the classpath, you get this error:

Caused by: java.lang.ClassCastException: class org.springframework.cloud.contract.verifier.builder.handlebars.HandlebarsJsonPathHelper cannot be cast to class com.github.jknack.handlebars.Helper (org.springframework.cloud.contract.verifier.builder.handlebars.HandlebarsJsonPathHelper and com.github.jknack.handlebars.Helper are in unnamed module of loader 'app')
	at com.github.tomakehurst.wiremock.extension.responsetemplating.TemplateEngine.addHelpers(TemplateEngine.java:113)
	at com.github.tomakehurst.wiremock.extension.responsetemplating.TemplateEngine.<init>(TemplateEngine.java:77)
	at com.github.tomakehurst.wiremock.extension.Extensions.configureTemplating(Extensions.java:144)
	at com.github.tomakehurst.wiremock.extension.Extensions.load(Extensions.java:113)
	at com.github.tomakehurst.wiremock.core.WireMockApp.<init>(WireMockApp.java:108)
	at com.github.tomakehurst.wiremock.WireMockServer.<init>(WireMockServer.java:68)
	at org.springframework.cloud.contract.stubrunner.provider.wiremock.WireMockHttpServerStub.start(WireMockHttpServerStub.java:138)
	at org.springframework.cloud.contract.stubrunner.StubServer.start(StubServer.java:51)
	at org.springframework.cloud.contract.stubrunner.StubRunnerExecutor.startStubServers(StubRunnerExecutor.java:299)
	at org.springframework.cloud.contract.stubrunner.StubRunnerExecutor.runStubs(StubRunnerExecutor.java:95)
	at org.springframework.cloud.contract.stubrunner.StubRunner.runStubs(StubRunner.java:77)
	at org.springframework.cloud.contract.stubrunner.BatchStubRunner.runStubs(BatchStubRunner.java:47)
	at org.springframework.cloud.contract.stubrunner.spring.StubRunnerConfiguration.batchStubRunner(StubRunnerConfiguration.java:88)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:155)
	... 62 more

As I understand, this happens because com.github.tomakehurst.wiremock.extension.responsetemplating.TemplateEngine is taken from regular wiremock dependency, which expects com.github.jknack.handlebars.Helper, but spring cloud HandlebarsJsonPathHelper uses shaded wiremock.com.github.jknack.handlebars.Helper

For those who encountered the same issue the fix for the time being would be to exclude wiremock from the org.wiremock.integrations:wiremock-spring-boot:4.0.8 like that:

testImplementation("org.wiremock.integrations:wiremock-spring-boot:4.0.8") {
        exclude group: 'org.wiremock', module: 'wiremock'
        exclude group: 'org.wiremock', module: 'wiremock-jetty12'
}

so TemplateEngine is taken from spring cloud's instead.

Sample dependencies:

testImplementation "org.wiremock.integrations:wiremock-spring-boot:4.0.8"
testImplementation "org.springframework.cloud:spring-cloud-starter-contract-stub-runner"

Sample class:

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.MOCK, classes = ExampleApplication.class)
@AutoConfigureWebMvc
@AutoConfigureJsonTesters
@AutoConfigureStubRunner(ids = "com.example:rest-api:+:stubs:8099")
@ActiveProfiles("TEST")
class RestApiContractTest { }

[marcingrzejszczak]

The maintainers of WireMock Spring Boot created a wiremock-spring-boot-standalone dependency so we should document that usage. Anybody cares to file a PR?

[marcingrzejszczak]

Actually there is a way to solve this - use a wiremock-spring-boot-standalone. We need to document this!