Java 21 support

[oleg-nenashev]

Proposal

Java 21 LTS is coming out soon, and it would be great to ensure that WireMock is fully compatible with it. WireMock may work out of the box, but we would still need official images, documentation, and CI runs against this baseline.

References

• https://openjdk.org/projects/jdk/21/
• https://www.infoq.com/news/2023/03/java-20-so-far/

[SimonVerhoeven]

The Gradle wrapper will also need to be updated to 8.4.

[mikebell90]

Are there known issues ? It seems problematic to wait a year until after java 21 comes out for an official wiremock 4 support

[matiwinnetou]

Doesn't seem compatible...

works with JDK 17 but fails with JDK 21

	testImplementation("org.wiremock:wiremock:3.3.1")

Error I am getting:

java.lang.IncompatibleClassChangeError: class org.eclipse.jetty.http2.server.HttpChannelOverHTTP2 has interface org.eclipse.jetty.server.HttpChannel as super class
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1027)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
	at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:862)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:760)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:681)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:639)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
	at org.eclipse.jetty.http2.server.AbstractHTTP2ServerConnectionFactory.<init>(AbstractHTTP2ServerConnectionFactory.java:82)
	at org.eclipse.jetty.http2.server.HTTP2ServerConnectionFactory.<init>(HTTP2ServerConnectionFactory.java:53)
	at org.eclipse.jetty.http2.server.HTTP2CServerConnectionFactory.<init>(HTTP2CServerConnectionFactory.java:53)
	at org.eclipse.jetty.http2.server.HTTP2CServerConnectionFactory.<init>(HTTP2CServerConnectionFactory.java:48)
	at com.github.tomakehurst.wiremock.jetty11.Jetty11HttpServer.createHttpConnector(Jetty11HttpServer.java:53)
	at com.github.tomakehurst.wiremock.jetty.JettyHttpServer.<init>(JettyHttpServer.java:89)
	at com.github.tomakehurst.wiremock.jetty11.Jetty11HttpServer.<init>(Jetty11HttpServer.java:44)
	at com.github.tomakehurst.wiremock.jetty.JettyHttpServerFactory.buildHttpServer(JettyHttpServerFactory.java:31)
	at com.github.tomakehurst.wiremock.WireMockServer.<init>(WireMockServer.java:81)
	at com.github.tomakehurst.wiremock.WireMockServer.<init>(WireMockServer.java:123)
	at org.cardano.foundation.voting.api.BaseTest.setUp(BaseTest.java:62)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	Suppressed: java.lang.NullPointerException: Cannot invoke "com.github.tomakehurst.wiremock.WireMockServer.stop()" because "this.wireMockServer" is null
		at org.cardano.foundation.voting.api.BaseTest.tearDown(BaseTest.java:230)
		at java.base/java.lang.reflect.Method.invoke(Method.java:580)
		at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
		at java.base/java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1116)
		... 1 more

those lines are as simple as:

        wireMockServer = new WireMockServer(9090);
        wireMockServer.start();

mati@Mateuszs-MBP voting-ledger-follower-app % java --version
openjdk 21 2023-09-19 LTS
OpenJDK Runtime Environment Corretto-21.0.0.35.1 (build 21+35-LTS)
OpenJDK 64-Bit Server VM Corretto-21.0.0.35.1 (build 21+35-LTS, mixed mode, sharing)

[marcindabrowski]

@matiwinnetou are you sure that in your project you are not importing any bom file? For example I had the same error with Spring Boot 3.2 because in their bom there is Jetty 12, which is not compatible with Jetty 11 used by Wiremock.

[seroandone]

@marcindabrowski how did you end up excluding springboot jetty bom? I am facing the same issue

[seroandone]

thanks for that info @marcindabrowski i was able to resolve it, here is what i did, added the following segment to my pom.xml

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.eclipse.jetty</groupId>
      <artifactId>jetty-bom</artifactId>
      <version>11.0.18</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

This works, because, maven honors in the local pom.xml over the parent pom, or its parent.

Note: I am using,

• java 21
• springboot 3.2.0
• wiremock 3.3.1

Documenting failure attempt,

tried changing just the value of <jetty.version> to 11.0.18 in of my pom.xml, however that wont work as there is another bom org.eclipse.jetty.ee10 that references the same <jetty.version> property, which doesn't have the same versioning.

Please comment if there was a better resolution

[marcindabrowski]

I'm using Gradle, and for me this helped:

configurations.all {
    resolutionStrategy.eachDependency {
        if (requested.group == "org.eclipse.jetty") {
            useVersion("11.0.18")
            because("Jetty 12.x.x from Spring Boot 3.2.x is incompatible with Wiremock 3.3.x.")
        }
    }
}

But it only works when you are importing Spring bom like this:

implementation(platform("org.springframework.boot:spring-boot-dependencies:3.2.0"))

If you are using io.spring.dependency-management Gradle plugin it will not work, becuase in Spring Boot 3.2.0 they added new Jetty depenedency jetty-ee10-bom, which do not have 11 version, and with this plugin you can just override Spring bom property like this:

ext["jetty.version"] = "11.0.18"

So the only solution I found is to remove this plugin and import Spring Bom in Gradle way.

[Saljack]

These mentioned errors are not connected to Java 21 but to library mismatch (Jetty in WireMock and Spring Booot).
But do not override jetty version or other hacky things. Just use wiremock-standalone:

<dependency>
    <groupId>org.wiremock</groupId>
    <artifactId>wiremock-standalone</artifactId>
    <version>3.3.1</version>
    <scope>test</scope>
</dependency>

This version shades all dependencies and you do not need to change anything.