Issues with DummyInvocationUtils on Java 17

[jochenberger]

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I'm trying to move a project from Java 11 to Java 17 and I'm having issues with code that creates resource URLs.

linkTo(methodOn(EntityController.class)).getEntity(id).getHref()

The Controller method returns a CompletableFuture.

When I switch to Java 17, I get

java.lang.IllegalAccessException: module java.base does not open java.util.concurrent to unnamed module @6fdb1f78
	at java.base/java.lang.invoke.MethodHandles.privateLookupIn(MethodHandles.java:259) ~[na:na]
	at java.base/jdk.internal.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
	at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:576) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:363) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:585) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:110) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:108) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54) ~[spring-core-5.3.21.jar!/:5.3.21]
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
	at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:134) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:319) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:572) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:419) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.ObjenesisCglibAopProxy.createProxyClassAndInstance(ObjenesisCglibAopProxy.java:57) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:206) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:110) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.hateoas.server.core.DummyInvocationUtils.getProxyWithInterceptor(DummyInvocationUtils.java:203) ~[spring-hateoas-1.5.1.jar!/:1.5.1]
	at org.springframework.hateoas.server.core.DummyInvocationUtils.access$000(DummyInvocationUtils.java:37) ~[spring-hateoas-1.5.1.jar!/:1.5.1]
	at org.springframework.hateoas.server.core.DummyInvocationUtils$InvocationRecordingMethodInterceptor.invoke(DummyInvocationUtils.java:96) ~[spring-hateoas-1.5.1.jar!/:1.5.1]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.example.EntityController$$EnhancerBySpringCGLIB$$8127ed24.getEntity(<generated>) ~[classes!/:na]

If I add --add-opens=java.base/java.util.concurrent=ALL-UNNAMED, I get

java.lang.IllegalArgumentException: $java.util.concurrent.CompletableFuture$$EnhancerBySpringCGLIB$$2c5f9ec4 not in same package as lookup class
	at java.base/java.lang.invoke.MethodHandleStatics.newIllegalArgumentException(MethodHandleStatics.java:167) ~[na:na]
	at java.base/java.lang.invoke.MethodHandles$Lookup$ClassFile.newInstance(MethodHandles.java:2283) ~[na:na]
	at java.base/java.lang.invoke.MethodHandles$Lookup.makeClassDefiner(MethodHandles.java:2318) ~[na:na]
	at java.base/java.lang.invoke.MethodHandles$Lookup.defineClass(MethodHandles.java:1843) ~[na:na]
	at java.base/jdk.internal.reflect.GeneratedMethodAccessor52.invoke(Unknown Source) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
	at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:577) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:363) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:585) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:110) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:108) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54) ~[spring-core-5.3.21.jar!/:5.3.21]
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
	at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:134) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:319) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:572) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:419) ~[spring-core-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.ObjenesisCglibAopProxy.createProxyClassAndInstance(ObjenesisCglibAopProxy.java:57) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:206) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:110) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.hateoas.server.core.DummyInvocationUtils.getProxyWithInterceptor(DummyInvocationUtils.java:203) ~[spring-hateoas-1.5.1.jar!/:1.5.1]
	at org.springframework.hateoas.server.core.DummyInvocationUtils.access$000(DummyInvocationUtils.java:37) ~[spring-hateoas-1.5.1.jar!/:1.5.1]
	at org.springframework.hateoas.server.core.DummyInvocationUtils$InvocationRecordingMethodInterceptor.invoke(DummyInvocationUtils.java:96) ~[spring-hateoas-1.5.1.jar!/:1.5.1]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.21.jar!/:5.3.21]
	at org.example.EntityController$$EnhancerBySpringCGLIB$$ee1b9f9d.getEntity(<generated>) ~[classes!/:na]
...

Please let me know if I can provide any more details.

[jochenberger]

Might be related to #27490 / 28138

[odrotbohm]

Are you using Spring Framework / HATEOAS on the module path? Or does the error also appear in a plain classpath arrangement? A reproducer would be super helpful.

[jochenberger]

I'm not sure what you mean. I'm using a Spring Boot REST application, I'm starting the fat jar with java -jar.

[jochenberger]

Here you go: demo.zip

Start the project using ./gradlew bootRun with Java 17 and call curl localhost:8080/help.

Please let me know if you need anything else.

For reference, the controller code in the demo project looks like this:

public class DemoController {

    @GetMapping("/entity/{id}")
    public CompletableFuture<Object> getEntity(@PathVariable String id) {
        return CompletableFuture.completedFuture(Map.of("id", id));
    }

    @GetMapping("/help")
    public Object getHelp() {
        return Map.of("urls",
                Map.of("entity", WebMvcLinkBuilder
                        // this is where the exception occurrs
                        .linkTo(WebMvcLinkBuilder.methodOn(DemoController.class).getEntity(null))
                        .withSelfRel().getHref()));
    }
}

The stacktrace is

2022-06-29 14:34:38.143 ERROR 42435 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class java.util.concurrent.CompletableFuture: Common causes of this problem include using a final class or a non-visible class; nested exception is org.springframework.cglib.core.CodeGenerationException: java.lang.IllegalAccessException-->module java.base does not open java.util.concurrent to unnamed module @4cfaf581] with root cause

java.lang.IllegalAccessException: module java.base does not open java.util.concurrent to unnamed module @4cfaf581
        at java.base/java.lang.invoke.MethodHandles.privateLookupIn(MethodHandles.java:259) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
        at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:576) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:363) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:585) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:110) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:108) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54) ~[spring-core-5.3.21.jar:5.3.21]
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
        at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:134) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:319) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:572) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:419) ~[spring-core-5.3.21.jar:5.3.21]
        at org.springframework.aop.framework.ObjenesisCglibAopProxy.createProxyClassAndInstance(ObjenesisCglibAopProxy.java:57) ~[spring-aop-5.3.21.jar:5.3.21]
        at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:206) ~[spring-aop-5.3.21.jar:5.3.21]
        at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:110) ~[spring-aop-5.3.21.jar:5.3.21]
        at org.springframework.hateoas.server.core.DummyInvocationUtils.getProxyWithInterceptor(DummyInvocationUtils.java:203) ~[spring-hateoas-1.5.1.jar:1.5.1]
        at org.springframework.hateoas.server.core.DummyInvocationUtils.access$000(DummyInvocationUtils.java:37) ~[spring-hateoas-1.5.1.jar:1.5.1]
        at org.springframework.hateoas.server.core.DummyInvocationUtils$InvocationRecordingMethodInterceptor.invoke(DummyInvocationUtils.java:96) ~[spring-hateoas-1.5.1.jar:1.5.1]
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.21.jar:5.3.21]
        at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.21.jar:5.3.21]
        at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.21.jar:5.3.21]
        at com.example.demo.DemoController$$EnhancerBySpringCGLIB$$d4c33d56.getEntity(<generated>) ~[main/:na]
        at com.example.demo.DemoController.getHelp(DemoController.java:25) ~[main/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
...

[odrotbohm]

I'm not sure what you mean. I'm using a Spring Boot REST application, I'm starting the fat jar with java -jar.

That's helpful, thanks!

Here you go: demo.zip

Start the project using ./gradlew bootRun with Java 17 and call curl localhost:8080/help.

Please let me know if you need anything else.

That, too! I'll have a look ASAP.

[jochenberger]

If I omit the CompletableFuture and return Map directly, it works fine. Curiously, it also seems to work if I use Future instead of CompletableFuture in the method signature. :man_shrugging:

[odrotbohm]

For interfaces, JDK proxies are generated. For concrete types, we need to create a class-based (CGLib) proxy, which fails as the JDK rejects a reflective reference to the core JDK type. We're currently investigating the issue internally. Can you switch to Future as the return type of the controller method as a workaround? Usually, those methods are not really called directly anyway.

[jochenberger]

I'll try that. I only just found that workaround myself. :wink:

[jochenberger]

Looks promising. I think I'll be able to work around the issue for us thanks to your quick and helpful response. Thanks! Feel free to close the issue.

[odrotbohm]

Glad to hear that! I'll keep it around until we come to an official conclusion. Could be a fix or just some tweak to the documentation outlining the limitation or configuration flags to set when running the app to re-enable those types being proxied.

[sbrannen]

Hi @jochenberger,

If I add --add-opens=java.base/java.util.concurrent=ALL-UNNAMED, I get

@jhoeller suggested that you instead use --add-opens=java.base/java.lang=ALL-UNNAMED to open up the protected ClassLoader.defineClass(...) method used by Spring's CGLIB fork.

What happens if you instead do that?

[jochenberger]

@sbrannen, yes, that does seem to help. At least with the demo project. I didn't try the other one yet.