Why does ClassNotFoundException appear in Interceptor when running in SpringBoot?

Below is my agent code (target VM running in kubernetes)： The AgentMain:

import net.bytebuddy.ByteBuddy;
import net.bytebuddy.agent.builder.AgentBuilder;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.dynamic.ClassFileLocator;
import net.bytebuddy.dynamic.DynamicType;
import net.bytebuddy.dynamic.scaffold.TypeValidation;
import net.bytebuddy.implementation.MethodDelegation;
import net.bytebuddy.pool.TypePool;
import net.bytebuddy.utility.JavaModule;

import java.lang.instrument.ClassDefinition;
import java.lang.instrument.Instrumentation;
import java.lang.instrument.UnmodifiableClassException;

import static net.bytebuddy.matcher.ElementMatchers.named;
import static net.bytebuddy.matcher.ElementMatchers.takesArguments;

public class AgentMain {
     public static void agentmain(String agentArgs, Instrumentation instrumentation) throws Exception {
            ClassLoader springBootClassLoader = ..//get LaunchedURLClassLoader from instrumentation.getAllLoadedClasses();
            ClassLoader oriParent = springBootClassLoader.getParent();

//1. Clear LaunchedURLClassLoader's parent to make sure ApiClientInterceptor is loaded by springBootClassLoader
// Therefore, the classes that ApiClientInterceptor depends on are also loaded from springBootClassLoader.
            clearSpirngCLParent();  

            File jarFile = new File("/backup/OpsAgent-1.0-SNAPSHOT-jar-with-dependencies.jar");
            injectToURLClassLoader(new URL[]{jarFile.toURI().toURL()}, (URLClassLoader) springBootClassLoader);

            addTransformerApiClient(instrumentation, TypePool.Default.of(ClassFileLocator.ForClassLoader.of(springBootClassLoader)));

            //2. Load the Interceptor while springBootClassLoader has no parent loader
            Class<?> apiClientInterceptorClz = springBootClassLoader.loadClass("org.example.ApiClientInterceptor");
            System.out.println("apiClientInterceptorClz:" + apiClientInterceptorClz.getClassLoader());

            restoreSpringCLParent(oriParent);
     }

     private static void addTransformerApiClient(Instrumentation instrumentation, final TypePool typePool) {
        new AgentBuilder.Default()
                .with(AgentBuilder.RedefinitionStrategy.RETRANSFORMATION)
                .disableClassFormatChanges()
                .type(named("io.kubernetes.client.openapi.ApiClient"))
                .transform(new AgentBuilder.Transformer() {
                    @Override
                    public DynamicType.Builder<?> transform(DynamicType.Builder<?> builder,
                                                            TypeDescription typeDescription,
                                                            ClassLoader classLoader,
                                                            JavaModule module,
                                                            ProtectionDomain protectionDomain) {
                        System.out.println("transform ApiClient trigger");
                        return builder.method(named("executeAsync").and(takesArguments(3)))
                                .intercept(MethodDelegation.to(typePool.describe("org.example.ApiClientInterceptor").resolve()));
                    }
                }).installOn(instrumentation);
     }

     private static void clearSpirngCLParent()  {
        Field parentF = ClassLoader.class.getDeclaredField("parent");
        parentF.setAccessible(true);
        parentF.set(springCL, null);
     }

     private static void restoreSpringCLParent(ClassLoader oriParent)  {
        Field parentF = ClassLoader.class.getDeclaredField("parent");
        parentF.setAccessible(true);
        parentF.set(springCL, oriParent);
     }
}

ApiClientInterceptor:

import io.kubernetes.client.openapi.ApiCallback;
import io.kubernetes.client.openapi.ApiClient;
import io.kubernetes.client.openapi.ApiException;
import net.bytebuddy.implementation.bind.annotation.Argument;
import net.bytebuddy.implementation.bind.annotation.This;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Response;

import java.io.IOException;
import java.lang.reflect.Type;

public class ApiClientInterceptor {
    public static <T> void executeAsync(@This ApiClient apiClient, @Argument(0) Call call, @Argument(1) Type returnType, @Argument(2) ApiCallback<T> callback) {

        //3. test if can load
        Class<?> c= springBootClassLoader.loadClass("okhttp3.Callback");
        //it prints "org.springframework.boot.loader.LaunchedURLClassLoader@1698c449"
        System.out.println(c.getClassLoader());

        //4. this line throws ClassNotFoundException
        Callback cb= new Callback() {
             @Override
            public void onFailure(Call call, IOException e) {}
            ...  
        };
    }
}

Step 4's stacktrace:

Exception in thread "kube-pipeline-exec-1" java.lang.NoClassDefFoundError: okhttp3/Callback
    at java.base/java.lang.ClassLoader.defineClass1(Native Method)
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:800)
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:698)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:621)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:576)
    at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:151)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    at org.example.ApiClientDelegation.executeAsync(ApiClientDelegation.java:27)
    at io.kubernetes.client.openapi.ApiClient.executeAsync(ApiClient.java)
    at io.kubernetes.client.openapi.apis.CoreV1Api.deleteNamespacedConfigMapAsync(CoreV1Api.java:22661)
    at coopwire.ops.k8scce.plpeline.sink.ConfigMapDeleteSink.accept(ConfigMapDeleteSink.java:25)
    at coopwire.ops.provider.k8s.core.K8PipelineExecutor.doBegin(K8PipelineExecutor.java:72)
    at coopwire.ops.provider.k8s.core.K8PipelineExecutor$2.run(K8PipelineExecutor.java:46)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.lang.ClassNotFoundException: okhttp3.Callback
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    ... 20 more

pom.xml:

<dependencies>
        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>4.9.2</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>net.bytebuddy</groupId>
            <artifactId>byte-buddy</artifactId>
            <version>1.14.11</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/net.bytebuddy/byte-buddy-agent -->
        <dependency>
            <groupId>net.bytebuddy</groupId>
            <artifactId>byte-buddy-agent</artifactId>
            <version>1.14.11</version>
        </dependency>

        <dependency>
            <groupId>io.kubernetes</groupId>
            <artifactId>client-java</artifactId>
            <version>16.0.0</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

I am very confused, because i think 3 and 4 do the same thing. Why does 4 throw an exception and 3 succed?

What could be the reason for this, is it related to the fact that Callback is in kotlin language or it‘s creating anonymous class ? Thanks . orz...

raphw / byte-buddy

Why does ClassNotFoundException appear in Interceptor when running in SpringBoot? #1593